JPH1115718A - Distributed file system and gateway computer used in the distributed file system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distributed file system which has a high cache hit ratio and also a fast access speed. SOLUTION: A distributed file system 2 includes a server computer 4, a gateway computer 6, client computers 8 and 10, an external network 36 which connects the computers 4 and 6 and an internal network 38 which connects the computer 6 and the computers 8 and 10. A cache distribution controlling part 18 of the computer 6 supervises an access log file 14 and sends a file object acquisition request to a client proxy server process 30 of the computer 10 except the computer 8 that performs file object acquisition. The process 30 sends an acquisition request to a master proxy server process 12 and receives a file object.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed file system in which a server computer and a plurality of client computers distributed on a network are interconnected via a gateway computer, and a gateway computer used in the distributed file system. In particular, the present invention relates to a distributed file system having a high cache hit rate and a high access speed, and a gateway computer used in the distributed file system.

[0002]

2. Description of the Related Art In a conventional distributed file system, a read request for a file object on a server computer from a plurality of client computers is relayed once by a gateway computer on the way. Here, the file object refers to a set of a network protocol used by the file system, a network address (name of the server computer), a file name, and a file entity. Of these, a set of a network protocol, a network address, and a file name is called a file object name.

As a conventional distributed file system, there is a file input / output method of a distributed file system disclosed in Japanese Patent Application Laid-Open No. 4-313126. In this method, the file object read from the server computer by the gateway computer is relayed to the client computer and stored in a cache file (disk, semiconductor memory, etc.) inside the gateway computer. When an access request for the same file object is received from the client computer, the last modification time of the file object stored in the cache file of the gateway computer is compared with the last modification time of the file object stored in the server computer. If the content of the stored file object is old and the cache file stored in the server computer is newer, the file object is extracted from the server computer.
The file object is relayed to the client computer, and the cache file of the gateway computer is updated. Conventionally, such a control method is performed. If the file object is not stored in the cache file, the file object is relay-transferred from the server computer, and the file object is written in the cache file. The speed of the relay access is improved by taking out from the relay.

A proxy server device on the Internet is a gateway computer having such a cache mechanism. The Internet is based on TCP / IP
(Transmission control protocol / internet protocol
) Is a global network. TCP / I
A regional distributed multimedia information providing system, which is a network using P, is called the World Wide Web (WWW). WWW can handle file objects distributed on the network. These file objects are not only text, but also various data such as images, voices, and video images. They are attractive for both information providers and information users (users), so that WWW traffic on the network Is exploding. In a WWW system, a user of a client computer can access information constituted by file objects held by server computers distributed over a network one after another simply by using browser software having a graphical user interface mounted on the client computer. It has become popular because of its simplicity, and it has also become popular as the basis for information system infrastructure inside a company. For example, in-house standards, rules, and notices are also posted as WWW file objects on server computers, and employees can access them using viewing software.

[0005] In such a WWW system, the Hypertext Transfer Protocol built on the TCP / IP protocol is used.
l File objects are transferred using a protocol called (HTTP). As a method of transferring a file object using HTTP, relay transfer of a file object is widely performed like a gateway computer disclosed in Japanese Patent Application Laid-Open No. 4-313126.
The relayed file object is cached in the gateway device. Such a gateway computer that speeds up access to file objects on a network and reduces Internet traffic is particularly called a “proxy server device”. proxy The proxy of the server means proxy, but as the name implies, when a client computer accesses a file object of a WWW server computer on a network, it accepts the access request on behalf of the server and transfers the file object. It relays.

Referring to FIG. 15, the proxy server device 112 in the WWW system 110 will be described. WWW
The system 110 includes a server computer 4 for storing file objects, and a proxy server device (gateway computer) 112 for relaying and transferring file objects.
And the client computer 8 and the client computer 8
An internal network 38 for connecting the proxy server device 112 to each other, and an external network 3 for connecting the proxy server device 112 and the server computer 4 to each other.
6 is included. The client computer 8 includes browser software 24 for executing a process of transmitting a read request for a file object, receiving various data including a file object from the proxy server device 112, and presenting the received data to a user. . The proxy server device 112 is a master proxy server process 12 for executing a file object transfer process, an access log file 14 for storing an access log to the server computer 4, and for temporarily storing a file object. Cache file 16.

[0007] As a method of realizing the proxy server device 112, a proxy server process 12 such as W3C httpd or DeleGate is generally run as a process on a computer running a UNIX OS (trademark of X / Open) connected to a network. ing. The UNIX OS is an operating system (OS) that realizes multi-user by multi-process.
m).

Referring to FIG. 2, proxy server device 112
Is a CPU 42 for executing a UNIX OS and a memory 44
, I / O unit 46, file device 50, network
And an I / O unit 48. The file device 50 stores the access log file 14 and the cache file 16 described above.
And various work files.

First, the client computer 8 of the internal network issues a file object read request (access request) to the proxy server device 112 in order to obtain the file object in the server computer 4. This is received by the master proxy server process 12, which is software running in the proxy server device 112.
The master proxy server process 12 accesses the cache file 16 and checks whether there is a file object requested to be read. If the file object is cached, master proxy server process 1
2. Compare the expiration date specific to the cache file with the last modification time of the cached object file
If the file object is valid, it is read from the cache file 16 and transmitted to the client computer 8 in the internal network 38.

If the file object does not exist in the cache file 16 or the expiration date has passed even if it exists, a read request for the file object is transmitted to the server computer 4 in the external network 36. .

The server computer 4 having received the file object read request reads the file object from its own file and sends it to the master proxy server process 12. The master proxy server process 12 in the proxy server device 112 that has received the file object,
The client computer name, the access date and time, and the file object name (that is, a set of the network protocol, the network address of the server computer, and the file name) are written in the access log file 14 as an access log.

At the same time, the data including the file object is transferred to the client computer 8 of the internal network 38, and the file object is written in the cache file 16. At this time, the HTTP header information of the transfer, the writing date of the file object, and the access date and time are recorded in the cache file 16.

One of the guidelines indicating the performance of the proxy server device 112 is a cache hit ratio. This is because the file object to be accessed is cache file 1
6 shows the ratio present in 6. Let the cache hit rate be H. Assuming that an average transfer time when transferring a file object existing in the server computer 4 to the client computer 8 is Tx, and an average transfer time when transferring the file object existing in the cache file 16 to the client computer 8 is Ti. , Average transfer time Tm for transferring file objects to client computer 8
Is as follows: Tm = (1−H) × Tx + H × Ti (1) Here, the transfer speed in the internal network 38 is usually sufficiently high. Therefore, since Ti can be regarded as 0, it can be approximated as Tm = (1−H) × Tx (2).

On the other hand, there is no cache file 16
Considering a proxy server device, since all file objects requested to be read from the client computer 8 are transferred from the server computer 4, the average transfer time when transferring the file objects to the client computer 8 is considered.
Tm2 becomes Tm2 = Tx (3).

In the proxy server device 112 having the cache file 16, if the average transfer time Tm2 of the proxy server having no cache file 16 is 1,
The time has been reduced to (1-H). For example, if the hit rate is 50% (H = 0.5), 100% −50% = 5
It is reduced to 0%. If the hit rate is 30%, 1
00% -30% = 70%, and the waiting time is reduced by 30%.

In order to improve the cache hit rate, it is necessary to cache a large number of file objects in the file device 50 having a capacity as large as possible. This increases the probability that the same file object will be used again.

According to our experience, the cache hit rate is 0% when the capacity of the cache file 16 is 0 MB (Mega Bytes), but is about 30% at about 100 MB, 40% at 300 MB, and about 50% at about 1 GB. It is known that a cache hit rate can be obtained.

This is because there is a high probability that a file object accessed by a certain user has already been accessed by another user and is cached in the gateway computer.

These proxy server devices 112 can be connected to a network in multiple stages. The proxy server device 112 with the cache file 16 is also operated as a process inside the client computer 8. For example, Netscape Navigator (Netscape Commutor) which is browser software 24 for browsing file objects used in the client computer 8
nications trademark) has a browser cache. About 5 MB is standardly set as the maximum storage capacity. This is a capacity capable of storing about 100 pages of sentences. Also, only data stored in the browser cache accessed by the user is to be reused.

Here, terms of the WWW system will be described. In a WWW system, file object names distributed on a network are called Uniform Resource Locator.
(URL) is specified and specified.

An example of a URL is shown below. http://www.xxx.co.jp/test/index.html http indicates the protocol to be used. www.xxx.co.jp indicates the address of the server computer (HTTP server computer) 4 on the network, and is selected so that there is no identical one on the network. /test/index.html indicates the file name of the server computer 4.

The master proxy server process 12 generates an access log (file object transfer record) according to a format called a common log format as a relay record of the file object. It includes the name of the client computer that sent the file object access request, the time, the HTTP method (file acquisition request), the status code of the server computer 4, and the data size of the file object. The access log is stored in the access log file 14. An example of an access log file is shown below. Client computer name--[Time] "GET http: // nar
agw.sharp.co.jp/oldindex.html HTTP / 1.0 ”200 1717 Client computer name--[Time]“ GET http: // nar
agw.sharp.co.jp/sharpcolor.gif HTTP / 1.0 ”200 173
0 Client computer name--[Time] “GET http: // nar
agw.sharp.co.jp/isg.mono.gif HTTP / 1.0 ”200 3331 Client computer name--[Time]“ GET http: // nar
agw.sharp.co.jp/Shoin.gif HTTP / 1.0 ”200 17936 Client computer name--[Time]“ GET http: // nar
agw.sharp.co.jp/Zaurus.gif HTTP / 1.0 ”200 16859 Client computer name--[Time]“ GET http: // nar
agw.sharp.co.jp/Prostation.gif HTTP / 1.0 ”200 163
45 Client computer name--[Time] “GET http: // nar
agw.sharp.co.jp/isg.gif HTTP / 1.0 ”200 20782 Client computer name--[Time]“ GET http: // nar
agw.sharp.co.jp/S2.gifHTTP/1.0 "200 11635 The status code of the server computer 4 is a response represented by a three-digit number issued by the server computer 4 to a request from the client computer 8. For example, if the status code is 2
00 indicates that the request has been successfully accepted. The first digit of the status code indicates the category, 1,
Any number of 2, 3, 4, 5 is used. 200
The status code in the series indicates that the request of the client computer 8 has been understood without any problem. A status code in the 300s indicates that the file object needs to be retransferred from the server computer 4. The 400s status code is
This indicates that the client computer 8 has accessed a non-existent URL. Status codes in the 500s indicate errors of the server computer 4. Also, status codes in the hundreds are reserved for future use and are not currently used.

The data size of the file object indicates the number of bytes of the file object as the name implies.

As described above, in the conventional distributed file system, the cache object 16 is cached in the cache file 16 in the proxy server device 112 to improve the cache hit rate.

[0025]

However, during business hours (especially during breaks), access from the client computer 8 tends to concentrate on the proxy server device 112. In this case, the communication within the internal network 38 becomes congested, and the speed cannot be said to be sufficiently high. Therefore, the value of the second item of Expression (1) increases, and the approximation of Expression (2) does not hold. On the other hand, the load on the proxy server device 112 also increases, and the response speed when reading the file object from the cache file 16 decreases. Therefore, it is necessary to accumulate file objects in the client computer 8 as much as possible to reduce the load on the internal network.

On the other hand, the file object cached in the browser cache of the client computer 8 is
Only the data accessed by the user of the client computer 8. Therefore, the cache storage amount is overwhelmingly smaller than that used by a large number of client computers 8 such as the proxy server device 112. Also,
The hit rate cannot be increased because data accessed by other users is not stored.

The present invention has been made to solve these problems, and an object of the present invention is to provide a distributed cache having a high cache hit rate and a high access speed. It is to provide a file system.

The object of the invention described in claim 3 is that of claim 1
Another object of the present invention is to provide a distributed file system in which a file object cached in one client computer can be used by another client computer.

The object of the invention described in claim 5 is that of claim 2
Another object of the present invention is to provide a distributed file system capable of suppressing the delivery of a file object that a client computer does not want.

An object of the invention described in claims 6 to 9 is to provide a distributed file system capable of efficiently transmitting a file object in addition to the object of the invention described in claim 2.

An object of the invention described in claim 10 is, in addition to the object of the invention described in claim 2, to provide a distributed file system capable of caching a dynamically generated file object in a gateway computer. It is to be.

The object of the invention described in claims 11 to 13 is
An object of the present invention is to provide a gateway computer used in a distributed file system having a high cache hit rate and a high access speed.

The object of the invention described in claim 14 is, in addition to the object of the invention described in claim 12, a gateway computer used in a distributed file system capable of suppressing the delivery of a file object that a client computer does not want. It is to provide.

The objects of the invention described in claims 15 to 18 are as follows:
Another object of the present invention is to provide a gateway computer used in a distributed file system capable of efficiently transmitting a file object.

The object of the invention described in claim 19 is, in addition to the object of the invention described in claim 12, a gateway computer used in a distributed file system capable of caching dynamically generated file objects. It is to provide.

[0036]

According to a first aspect of the present invention, there is provided a distributed file system comprising: a server computer for receiving an access request and transmitting a file object corresponding to the access request; and a plurality of client computers. , A gateway computer, and a communication line for interconnecting the server computer and the plurality of client computers via the gateway computer, wherein each of the plurality of client computers temporarily stores the file object. A client cache file for holding, and a first for connecting to the gateway computer, transmitting the access request for acquiring the file object, receiving the file object, and writing the file object in the client cache file.
Wherein the gateway computer includes a cache file for temporarily storing the file object, and an access for storing reception record information when the file object is received from the server computer. A log file, the client connected to the access log file, receiving the access request from each of the plurality of client computers, acquiring the file object from the cache file or the server computer, and transmitting the access request To transmit the received record information to the client computer selected by a computer and the received record information and a predetermined selection method, write to the cache file as needed, and write the received record information to the access log file And a file object distribution means.

According to the first aspect of the present invention, the file object distribution means transmits the file object to the client computer which has transmitted the access request for acquiring the file object, and uses the reception record information and a predetermined selection method. The same file object is transmitted to the selected client computer other than the client computer. Therefore, the file objects are cached one after another in other client computers. Therefore, even if the client computer is carried to another network, it is the same as the cache of the gateway computer, and a distributed file system with a high cache hit rate and a high access speed can be provided.

In the distributed file system according to the second aspect of the present invention, in addition to the configuration of the first aspect, the file object distribution unit receives the access request from each of the plurality of client computers. Obtaining the file object from the cache file or the server computer, transmitting the file object to the client computer that transmitted the access request, writing the cache file if necessary, and storing the reception record information in the access log file. File object acquisition proxy means for writing, and for transmitting the access request to a client computer selected according to the reception record information and a predetermined selection method among the plurality of client computers connected to the access log file. File objects And a preparative access request transmitting means,
The first file object receiving means includes means for receiving the access request from the file object access request transmitting means and transmitting the access request to the file object acquisition proxy means.

According to the invention described in claim 2, according to claim 1
In addition to the functions and effects of the invention described in (1), the file object access request transmitting means transmits the access request to the client computer selected according to the reception record information and the predetermined selection method. The first file object receiving means of the client computer receives the access request and transmits it to the file object proxy means, so that the file object acquired by another client computer can be cached. Therefore, a distributed file system having a high cache hit rate can be provided. According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the client cache file is a removable storage medium.

According to the invention of claim 3, according to claim 1,
In addition to the functions and effects of the inventions described in (1) to (2), since the client cache file is removable, the file object stored in the cache file of one client computer can be used by another client computer. .

According to a fourth aspect of the present invention, in the distributed file system according to the second aspect of the present invention, the file object access request transmitting means includes a file object name recorded in the reception record information. The access request for acquiring the file object is transmitted in the order of the appearance frequency of.

According to the invention described in claim 4, according to claim 2,
In addition to the functions and effects of the invention described in (1), the file object access request transmitting means transmits an access request such that the file objects are cached in the client computer in order from the most accessed file object. Therefore, a file object with a higher hit rate can be cached in the client computer. Therefore, a distributed file system having a high cache hit rate can be provided.

According to a fifth aspect of the present invention, in the distributed file system according to the second aspect of the present invention, the file object access request transmitting means transmits the received record information including a predetermined character string to the received record information. The access request for acquiring the file object is transmitted while excluding the recorded file object name.

According to the invention described in claim 5, according to claim 2,
In addition to the functions and effects of the invention described in (1), the file object access request transmitting unit transmits an access request for acquiring a file object other than a file object name including a predetermined character string. Therefore, it is possible to suppress the delivery of the file object that the client computer does not want.

According to a sixth aspect of the present invention, in the distributed file system according to the second aspect of the present invention, the file object access request transmitting unit transmits the reception proxy unit based on the reception record information. The access request is transmitted to a client computer other than the client computer that has acquired the file object through the above.

According to the invention described in claim 6, according to claim 2,
In addition to the functions and effects of the invention described in (1), the file object access request transmitting means does not transmit the access request to the client computer which has already acquired the file object through the receiving proxy means. As a result, the client computer does not repeatedly acquire the file object, and the file object can be transmitted efficiently.

According to a seventh aspect of the present invention, in the distributed file system according to the second aspect of the present invention, the file object access request transmitting unit transmits a predetermined character string based on the reception record information. The client computer sends the access request for acquiring the file object for which the access request has been made.

According to the invention described in claim 7, claim 2 is provided.
In addition to the functions and effects of the invention described in (1), the gateway computer transmits only the file object for which the predetermined client computer has made an access request to the client computer. Therefore, the file object can be transmitted efficiently.

In the distributed file system according to the present invention, in addition to the configuration of the present invention, whether the gateway computer is connected to the cache file and holds the file object The file object access request transmitting means is further connected to the holding determination means, and only when the file object is held in the cache file, is the file object access request transmitting means connected to the holding judgment means. Means for controlling to transmit the access request for acquisition is included.

According to the invention described in claim 8, according to claim 2,
In addition to the functions and effects of the invention described in (1), the file object access request transmitting unit transmits an access request for acquiring the file object to the client computer only when the file object is held in the cache file. As a result, unnecessary access requests do not occur, and the file object can be transmitted efficiently.

In the distributed file system according to the ninth aspect of the present invention, in addition to the configuration of the second aspect, the file object distribution means transmits the file object within a predetermined parallel delivery number. Means for performing control so as to perform the operations in parallel are further included.

According to the invention of claim 9, according to claim 2,
In addition to the functions and effects of the invention described in (1), the file object distribution means performs the transmission of the file object in parallel within a predetermined parallel delivery number. As a result, the object can be transmitted efficiently.

The distributed file system according to the tenth aspect of the present invention has the structure of the second aspect,
The gateway computer is connected to the file object distribution means, and a temporary cache file for temporarily holding a dynamic file object among the file objects, and the dynamic file from each of the plurality of client computers. Receiving an access request for acquiring an object, reading the dynamic file object from the temporary cache file, and transmitting the access request to a client computer that has transmitted the access request. The reception record information includes information indicating whether the file object received from the server computer is the dynamic file object, and the cache file is a non-dynamic file object of the file objects. Temporarily storing the file object, and the file object distribution means further includes means for writing to the temporary cache file if the file object obtained from the server computer is the dynamic file object, The object access request transmitting means is connected to the access log file, refers to the reception record information, and, if the file object obtained from the server computer is the dynamic file object, among the plurality of client computers, Dynamic file object access request transmitting means for transmitting an access request for acquiring the dynamic file object to the client computer selected according to the reception record information and a predetermined selection method; Is connected to Le,
Referring to the reception record information, if the file object obtained from the server computer is the non-dynamic file object, a client selected according to the reception record information and a predetermined selection method among the plurality of client computers. A static file object access request transmitting unit for transmitting an access request for acquiring the non-dynamic file object to a computer, wherein each of the plurality of client computers includes the dynamic file object access request transmitting unit. And a second file object receiving means for transmitting the access request, receiving the dynamic file object, and writing the dynamic file object in the client cache file.

According to the tenth aspect, in addition to the effects and advantages of the second aspect, a dynamic file object is stored in a temporary cache file and transmitted to the client computer. Therefore, the dynamically generated file object can be cached in the gateway computer.

A gateway computer according to the invention of claim 11 receives a request for access, a server computer for transmitting a file object corresponding to the access request, transmits the access request, and receives the file object. A gateway computer used in a distributed file system including a plurality of client computers, a gateway computer, and a communication line for interconnecting the server computer and the plurality of client computers via the gateway computer. A cache file for temporarily holding the file object, an access log file for holding reception record information when the file object is received from the server computer, and each of the plurality of client computers. Yo Receives the access request, obtains the file object from the cache file or the server computer, transmits the received record information and the client computer selected by a predetermined selection method, and transmits the received file information to the cache file as necessary. File object distribution means for writing the received record information in the access log file.

According to the eleventh aspect of the present invention, the file object distribution means transmits the file object to the client computer which has transmitted the access request for acquiring the file object, and receives the reception record information other than the client computer. The same file object is transmitted to the client computer selected by the predetermined selection method. Therefore, the file objects are cached one after another in other client computers. Therefore, it is possible to provide a gateway computer used in a distributed file system having a high cache hit rate and a high access speed.

The gateway computer according to the twelfth aspect of the present invention provides the gateway computer according to the eleventh aspect of the present invention,
The file object distribution means receives the access request from each of the plurality of client computers,
Obtain the file object from the cache file or the server computer, transmit the file object to the client computer that transmitted the access request, write the cache file if necessary, and write the reception record information to the access log file. And a file connected to the access log file for transmitting the access request to a client computer selected according to the reception record information and a predetermined selection method among the plurality of client computers. Object access request transmission means.

According to the twelfth aspect of the present invention, in addition to the functions and effects of the eleventh aspect of the present invention, the client computer selected by the file object access request transmitting means in accordance with the reception record information and a predetermined selection method. Send an access request to. When the client computer receives the access request and transmits it to the file object proxy means, the file object acquired by another client computer can be cached. Therefore, it is possible to provide a gateway computer used in a distributed file system having a high cache hit rate.

The gateway computer according to the thirteenth aspect of the present invention provides the gateway computer according to the twelfth aspect of the present invention,
The file object access request transmitting unit transmits the access request for acquiring the file object in the order of appearance frequency of the file object name recorded in the reception record information.

According to the thirteenth aspect, in addition to the effects and advantages of the twelfth aspect, the file object access request transmitting means is configured to cache the file objects in the client computer in order from the most frequently accessed file objects. Send an access request to. For this reason,
A file object having a higher hit rate can be cached in the client computer. Therefore, it is possible to provide a gateway computer used in a distributed file system having a high cache hit rate.

A gateway computer according to a fourteenth aspect of the present invention provides the gateway computer according to the twelfth aspect of the present invention,
The file object access request transmitting unit transmits the access request for acquiring the file object by excluding the file object name including a predetermined character string recorded in the reception record information.

According to the fourteenth aspect of the invention, in addition to the functions and effects of the twelfth aspect, the file object access request transmitting means transmits a file object other than a file object name including a predetermined character string. Send an access request to get it. Therefore, it is possible to suppress the delivery of the file object that the client computer does not want.

The gateway computer according to the invention of claim 15 provides the gateway computer according to the invention of claim 12,
The file object access request transmission unit transmits the access request to a client computer other than the client computer that has acquired the file object through the reception proxy unit based on the reception record information.

According to the fifteenth aspect of the present invention, in addition to the functions and effects of the twelfth aspect, the file object access request transmitting means transmits the client computer which has already acquired the file object through the receiving proxy means. Do not transmit an access request. As a result, the client computer does not repeatedly acquire the file object, and the file object can be transmitted efficiently.

The gateway computer according to the sixteenth aspect of the present invention provides the gateway computer according to the twelfth aspect of the present invention,
The file object access request transmission means transmits the access request for acquiring the file object for which the client computer has made an access request, including a predetermined character string, based on the reception record information.

According to the sixteenth aspect of the present invention, in addition to the function and effect of the twelfth aspect of the present invention, the gateway computer transmits only the file object for which the predetermined client computer has made an access request to the client computer. I do. Therefore, the file object can be transmitted efficiently.

The gateway computer according to the seventeenth aspect of the present invention provides the gateway computer according to the twelfth aspect of the present invention,
The storage device further includes a holding determination unit connected to the cache file to determine whether or not the file object is stored.The file object access request transmission unit is connected to the storage determination unit, and Means for controlling to transmit the access request for acquiring the file object only when the file object is held in the cache file.

According to the seventeenth aspect, in addition to the effects and advantages of the twelfth aspect, an access request for acquiring a file object only when the file object is held in a cache file is provided. To the client computer. As a result, unnecessary access requests do not occur, and the file object can be transmitted efficiently.

The gateway computer according to the eighteenth aspect of the present invention provides, in addition to the configuration of the twelfth aspect of the present invention,
The file object acquisition proxy unit further includes a unit for controlling transmission of the file object in parallel within a predetermined parallel delivery number.

According to the eighteenth aspect, in addition to the effects and advantages of the twelfth aspect, the file object distribution means performs the transmission of the file objects in parallel within a predetermined parallel delivery number. As a result, the object can be transmitted efficiently.

The gateway computer according to the nineteenth aspect of the present invention provides the gateway computer according to the twelfth aspect of the present invention,
A temporary cache file which is connected to the file object distribution means and temporarily holds a dynamic file object among the file objects;
An access request for acquiring the dynamic file object is received from each of the plurality of client computers, the dynamic file object is read from the temporary cache file, and transmitted to the client computer that transmitted the access request. Dynamic file object transmission means for receiving, the reception record information includes information indicating whether the file object received from the server computer is the dynamic file object, the cache file, The file objects that are not dynamic among the file objects are temporarily stored, and the file object distribution unit is configured to temporarily store the temporary cache files if the file objects acquired from the server computer are the dynamic file objects. The file object access request transmission means is connected to the access log file, refers to the reception record information, and converts the file object acquired from the server computer into the dynamic file. In the case of a file object, an operation for transmitting the access request for acquiring the dynamic file object to a client computer selected according to the reception record information and a predetermined selection method among the plurality of client computers. A file object access request transmitting means, connected to the access log file, referring to the reception record information, and if the file object obtained from the server computer is the non-dynamic file object, the plurality of client computers Within And a static file object access request transmitting means for transmitting the access request to obtain the file object is not a dynamic above the client computer which has been selected according to the received recording information and a predetermined selection method.

According to the nineteenth aspect, in addition to the functions and effects of the twelfth aspect, a dynamic file object is stored in a temporary cache file and transmitted to the client computer. Therefore, the dynamically generated file object can be cached in the gateway computer.

[0073]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a distributed file system 2 according to an embodiment of the present invention includes a server computer 4 for storing file objects and a gateway computer for relaying and transferring file objects. 6
An internal network 38 for interconnecting the client computers 8 and 10, the gateway computer 6, and an external network 36 for interconnecting the gateway computer 6 and the server computer 4. including. Client computer 8
Is browser software 24 for executing a process of transmitting a read request for a file object, receiving various data including a file object from the gateway computer 6, and presenting the received data to a user.
including. The client computer 10 includes browser software 26 for executing a process of presenting data to a user, and a reception control unit 28 for controlling reception of a file object and an access request from the gateway computer 6.

The reception control unit 28 controls the client computer 1
Client proxy server process 30 and client proxy server process 3 for updating the temporary cache, which are processes for making 0 work as a proxy server device.
4 and a client cache file 32 for temporarily storing file objects. The gateway computer 6 includes a master proxy server process 12 for executing a file object transfer process, an access log file 14 for storing an access log to the server computer 4, and a temporary storage for the file object. A cache delivery control unit 18 connected to the cache file 16 and the access log file 14 for transmitting a file object access request to the client computer 10 in accordance with the contents of the access log file and receiving the file object; A temporary cache file 20 for temporarily storing file objects, and a temporary cache update master pr for executing dynamic file object transfer processing
and an oxy server process 22. It is assumed that the client computer 8 does not have the reception control unit 28.

The client computer 10 is a notebook personal computer, and connects to a disk device of about 1 GB (Giga Bytes), a device for connecting to a high-speed network such as Ethernet, and a relatively low-speed network such as a telephone line. Device (such as a modem). At present, the disk device of notebook personal computers has become more than 1 GB, and the capacity is expected to increase in the future. In addition, an OS, application software, and the like are stored in the disk in advance at the time of shipment from the factory, but there is still an unused area of 500 MB or more.

The client computer 10 uses this free area as a cache (hereinafter, referred to as “client cache file 32”). Further, a file object being accessed by a user of another client computer 8 is received from the gateway computer 6 and stored in an empty area of the client cache file 32, thereby improving the cache hit rate of the client computer 10.

Referring to FIG. 2, gateway computer 6
Is a computer equipped with a UNIX OS or an OS capable of network control such as Windows 95 or Windows NT. The computer 42 has a CPU 42, a memory 44, an I / O unit 46, a client cache file 32, a list of delivery client computers, and a relay file. A file device 50 for storing a name recording file, a delivery list temporary storage buffer, a client computer name registration pattern, an exclusion pattern, a storage buffer, a matched pattern storage buffer, a transfer amount management storage buffer, and the like; and a network I / O unit 4
8 and an internal bus 49 for interconnecting them. The file stored in the file device 50 may be stored in the memory 44, and its meaning will be described later.

As in the gateway computer 6 described above, the client computer 10 has a CPU 42, a memory 44,
It includes an O unit 46, a file device 50, a network I / O unit 48, and the like. The reception control unit 28 incorporated in the client computer 10 is realized by executing proxy software with a cache function on the CPU 42.

The operation of the distributed file system 2 will be described with reference to FIGS. Referring to FIG. 3, it is assumed that the user accesses the file object http://www.sharp.co.jp/ stored in the server computer 4 using the browser software installed in the client computer 8. Access is performed via the gateway computer 6. The client computer 8 transfers the file object stored in the server computer 4 to the gateway computer 6
Receive via.

Referring to FIG. 4, cache delivery control unit 18 in gateway computer 6 operates at http://www.sharp.co.
The jp / data is also delivered to the client computers 10a, 10b and 10c. That is, the client computer 8
The file objects accessed by are automatically delivered to other clients.

As described above, according to our experience, the cache hit rate of the gateway computer 6 is 0% when the capacity of the cache file 16 is 0 MB, but is 30% at about 100 MB, 40% at 300 MB, and 50% at about 1 GB. It is known that it increases slowly as the cache size increases.

Therefore, as described above, a file object used by a user of another client computer other than the user can be received in the free disk area of the client computer, and its own client cache can be filled with about 300 MB of fresh data. For example, a hit rate of 40% or more can be obtained in the client cache.

The client computer 10 has a reception control unit 28 for performing a proxy operation.
6 makes a relay network access to the master proxy server process 12 via the reception control unit 28.

Normally, the client computer 10 is set to use the gateway computer 6 as a proxy server device.
y The server process is incorporated in the client computer (hereinafter, referred to as “client proxy server process 30”). When the browser software 26 issues a request to acquire a file object held by the server computer 4, the client proxy server process 30
Is set to operate as a proxy server device. Also, the client proxy server process 30
The setting is made to use the master proxy server process 12 of the upstream gateway computer 6. Client prox
y server process 30 is the master proxy server process 1
If there is no response when a file object acquisition request is made to the master proxy server process 1
2 so as not to use it. This will be described later.

It is assumed that the gateway computer 6 is connected to a plurality of client computers. The plurality of client computers include the client computer 10 having the reception control unit 28 and the client computer 8 not having the reception control unit 28.

The gateway computer 6 includes a master proxy server process 12 and a cache delivery control unit 18. These are processes that run on the CPU 42.
The master proxy server process 12 is realized by executing software easily available from the market. The user requests the client computer 8 equipped with the browser software 24 to acquire the file object in the server computer 4. The client computer 8
A request is sent to the gateway computer 6 to acquire the file object in the server computer 4. The master proxy server process 12 in the gateway computer 6 that has received the request transmits the request to the server computer 4.

Next, the operation of the master proxy server process 12 will be described. As described above, the file object is composed of a set of the protocol name, the network address name of the server computer, the file object name, and the file data entity.

The master proxy server process 12 is realized by the CPU 42 executing a proxy program stored in the memory 44. The master proxy server process 12 receives the file object transmission request from the client computer 8. The cache file 16 existing in the file device 50 is accessed via the I / O unit 46, the file object name is extracted from the cache file 16, and compared with the file object name of the file object transmission request. If the file object names match, the last modification time of the file object is read and compared with the current time. If it is within the validity period of the cache, the file object is extracted from the cache file 16 and returned to the client computer 8 via the network I / O unit 48.

If there is no copy of the file object in the cache file 16 or if the cache has expired, the network I / O
The transfer request of the file object is transmitted to the server computer 4 on the external network 36 via the unit 48.
The file object is read from the server computer 4, the file object is written in the cache file 16, and the last modification time of the file object is updated.
Further, the file object is transferred to the client computer 8 through the network I / O unit 48.

The master proxy server process 12 simultaneously transfers the file object and, each time one URL is relayed, requests the client computer to send a file object transmission request to the access log file 14 as an access log, the (last change) time, The file object name, status code from the server computer, the number of transfer bytes, etc. are recorded. This format is a standard, commonly referred to as the common log format, and can be used in any commercial or public proxy software.

Referring to FIG. 1, it is assumed that the user of client computer 8 has transmitted a request for obtaining a file object in server computer 4 to gateway computer 6. It is assumed that the cache file 16 has no file object and accesses the server computer 4 for the first time.

First, the browser software 24 makes a network connection to the master proxy server process 12 in the gateway computer 6, and sends a GET command.

The master proxy server process 12 having received the GET command makes a network connection to the server computer 4 and transmits the GET command.

The master proxy server process 12 reads out a file object from the server computer 4. The read file object is written in the cache file 16 and the access log is written in the access log file 1.
Write to 4. The browser software 24 reads the file object from the master proxy server process 12. The above is the relay operation.

The cache delivery control unit 18 reads the access log from the access log file 14, connects to the client proxy server process 30 of the client computer 10 having a reception control unit other than the client computer 8, and transmits a GET command. Client pr
Since the oxy server process 30 is a client proxy that uses the master proxy server process 12 as the upstream master proxy, the GET to the master proxy server process 12 is performed.
Send instructions.

The master proxy server process 12 reads a file object from the cache file 16 and
It is transmitted to the client proxy server process 30.

Client proxy server process 30
Accumulates this in the client cache file 32. As described above, the object file accessed by the user of the client computer 8 is also cached in the client cache file 32. Therefore, the user of the client computer 10 can use the browser software 26
When the file object of the server computer 4 is accessed via the client proxy server process 30 of the reception control unit 28 by using, the file object received in advance from the master proxy server Can be used.

Referring to FIG. 5 and FIG. 6, the detailed operation of each control unit will be described. Master proxy server process 1
Operation 2 has already been described. It is assumed that this is operating on port 10080. Cache delivery control unit 18
Is implemented by executing a process 60 called / usr / local / cachecast / cachecastd. [Step 1-1] At the start of the operation, the process 60
The file 62 called nts.txt is read from the file device 50. The name (corresponding to the IP address) of the client computer that delivers the cache (file object) is stored in the file 62 in advance. Also, for each client computer: Delivery start time 2. Delivery end time 3. Receiving port number 4. Maximum number of bytes transferred per hour 5. Client name matching pattern file name 6. Client name exclusion pattern file name 7. URL matching pattern list file name 8. URL exclusion pattern list file name It is assumed that the maximum number of parallel processes is described. The meaning of these will be described later.

The process 60 that has read these arguments is
The child processes 76 and 78 corresponding to the registered client computers to be cached are activated as background processes. The data in clients.txt is passed as an argument to child processes 76 and 78, respectively.

The names of the child processes 76 and 78 are / usr / locol / cachecast / cachecastw and / usr / locol / cachecast / cachecastwc, respectively. Arguments at startup are: cachecastw -h delivery client computer name -p port number \ -s start time -e end time -r maximum transfer bytes per hour \ -i URL matching pattern file name \ -x URL exclusion pattern file name \ -m Maximum number of parallel processes \ -c Client name matching pattern file name \ -X Client name exclusion pattern file name The format of the argument is the same for cachecastwc.

For example, if four client computers are to be delivered, the following eight processes are started. cachecastw -h client1 -p 8080 -s 9:00 -e 17:00 \ -i /usr/local/cachecast/client1/pattern.txt \ -x /client1/exclude.txt -c / usr / local / cachecast / cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & cachecastw -h client2 -p 8080 -s 9:00 -e 17:00 \ -i /usr/local/cachecast/client2/pattern.txt \ -x /client2/exclude.txt -c /usr/local/cachecast/cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & cachecastw -h client3 -p 8080 -s 9:00 -e 17: 00 \ -i /usr/local/cachecast/client3/pattern.txt \ -x /client3/exclude.txt -c /usr/local/cachecast/cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & cachecastw -h client4 -p 8080 -s 9:00 -e 17:00 \ -i /usr/local/cachecast/client4/pattern.txt \ -x /client4/exclude.txt -c / usr / local / cachecast /cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & cachecastwc -h client1 -p 8080 -s 9:00 -e 17:00 \ -i /usr/local/cachecast/client1/pattern.txt \ -x /client1/exclude.txt -c /usr/local/cachecast/cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & cachecastw c -h client2 -p 8080 -s 9:00 -e 17:00 \ -i /usr/local/cachecast/client2/pattern.txt \ -x /client2/exclude.txt -c / usr / local / cachecast / cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & cachecastwc -h client3 -p 8080 -s 9:00 -e 17:00 \ -i /usr/local/cachecast/client3/pattern.txt \ -x /client3/exclude.txt -c /usr/local/cachecast/cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & cachecastwc -h client4 -p 8080 -s 9:00 -e 17: 00 \ -i /usr/local/cachecast/client4/pattern.txt \ -x /client4/exclude.txt -c /usr/local/cachecast/cpattern.txt \ -X /usr/local/cacahecast/cexclude.txt & By this process, the cache is delivered to the four client computers 10 from 9:00 to 17:00. At this time, the reception control unit 28 of the client computer 10
Indicates that the service is being received on the TCP / IP port number 8080.

The four files cpattern.txt (client name matching pattern file 66), cexclude.txt (client name exclusion pattern file 64), and pattern.
txt (URL matching pattern file 68), exclude.txt
For (URL exclusion pattern file 70), the meaning and usage method will be described after the next step. [Step 1-2] Seek the file pointer to the end of the access log file 14. [Step 1-3] Read access log file The access log file 14 contains the gateway computer 6
The information obtained when the master proxy server process 12 operating under the condition that the file object specified by the URL is relayed by user access from the client computer 8 is written in the following format every moment. Client computer name--[Date and time offset]
“GET http://naragw.sharp.co.jp/S2.gif HTTP / 1.0”
Status code data size cache delivery control unit 18
4 is read out one line at a time via the FIFO buffer. The FIFO buffer is inside the OS, the write pointer indicates the line in which the master proxy server process 12 has written the access log in the access log file 14, and the read pointer is set in the line read by the cache delivery control unit 18. Is done.

The read URL name is stored in a memory variable called URLBUF. In the above format, the seventh field is the URL name (http://naragw.sharp.co.jp/S2.gi
f). The client computer name is stored in a variable called CLIENT. In the above format, the first field corresponds to it.

When reading the access log from the access log file 14, only the line including the GET method (GEThttp: //) is read. This is because the GET method is the master proxy
This is because the server process 12 has cached the file object in the cache file 16. Therefore, other POST method, HEAD method, etc. are skipped. If there is no corresponding GET method, the process returns to [step 1-3] and waits for generation of the next access log. [Step 1-4] Status Code Check The status code of the access log is 302 or 40
If it is 0 or more, it means that the file object does not exist in the server computer 4 or it needs to be accessed again.
p1-3]. [Step 1-5] URL check The URL included in the access log is the client computer 10
Check whether the conditions for delivering the file object to the server are satisfied. If the URL contains the "?" Character or certain strings (such as cgi-bin or htbin)
Return to [step 1-3]. "?", "Cgi-bin",
Those containing the characters "htbin" are dynamically generated file objects for transmitting information from the client computer to the server computer, and the file size is unknown. Therefore, it is not cached and does not match the purpose of delivering the cache. [Step 1-6] Object Read It is determined whether or not the target file object is an object cached in the cache file 16. Master proxy server process 12 has port number 1
If it is operating on 0080, the corresponding URL is obtained for this port number using the normal proxy usage method.

As a method for realizing this network access, a socket mechanism which is the basis of the network function of the UNIX OS is used. This is the same as the method in which the client computer 8 makes a network connection to the gateway computer 6 to obtain a file object.

The cache delivery control unit 18 uses socket ()
Using the sd file descriptor, which is the socket obtained by the system call, the specified gateway computer 6
A connect () system call is generated between the machine name and the TCP / IP port number 10080 to establish a connection.

Next, read / w of a normal file using sd
GET method to read the file object of server computer 4 specified by $ URLBUF as in rite
ite and read the data.

That is, the GET URL name HTTP / 1.0 \ r \ n \ r \ n is written to this file descriptor sd as a line feed code represented by a hexadecimal code of \ r = 0x0t \ n = 0x0a. by sd
Data is read up to EOF (end of file), and the header and data part of the file object of the specified URL are read from the master proxy server process 12. According to the HTTP specification, the header and the data section are separated by \ r \ n \ r \ n. The read header and data are stored in the temporary cache file 20. The file name of the temporary cache file 20 is, for example, the URL name is http: // naragw.
For sharp.co.jp/S2.gif, / usr / spool / cachecast / tmp
/http/naragw.sharp.co.jp/S2.gif [Step 1-7] Judgment of Cache Existence If the header read in [Step 1-6] has a Content-Length: field indicating the length of the normal data part, the file object corresponding to the cache file 16 is cached. . This is a feature of the header generated in the server computer 4 that provides different page contents for each user as a file object.
Generally, it is assumed that the gateway computer (proxy server device) 6 uses a plurality of client computers. Co
A file object having a header with no ntent-Length: field is relayed only to the client computer and is not cached in the cache file 16. If it is cached, the process branches to [step 1-8]. If it is not cached, the process branches to [step 1-9]. [Step 1-8] Processing with cache file 72 (file name / usr / spool / cachecast / tmp
/url.log) and write data in the following common log format. Client computer name--[Date and time offset] "GET URL name HTTP / 1.0" Status code Number of bytes Since the temporary cache file 20 is unnecessary, delete it and return to [step 1-3]. [Step 1-9] Processing without cache file 74 (file name / usr / spool / cachecast / tmp
/url.c.log), write data in the following common log format, and return to [step 1-3]. Client computer name--[Date and time offset] "GET URL name HTTP / 1.0" Status code Number of bytes The operation of the child process cachecastw will be described with reference to FIG. Multiple cachec started in [step1-1]
The astw process is actually responsible for delivering the URL file object. One of the operations will be described step by step. One process is allocated to the child process cachecastw for each client computer. cachecastw
Is invoked in the following format: cachecastw -h Delivery client computer name -p Port number \ -s Start time -e End time \ -r Maximum transfer bytes per hour \ -i URL match pattern file name \ -x URL exclusion pattern file name \ -m Maximum parallel process Number \ -c Client name matching pattern file name \ -X Client name exclusion pattern file name In the following description, the delivery client computer name is $ RECEI
It is assumed that the VER and the port number are referred to by a variable name of $ PORT. [Step 2-1] Startup When started, cachecastw checks whether or not the specified start time has passed. The current time is obtained from the OS system call. If it is before the start time, sleep until the start time and wait. When the start time comes, the process proceeds to [step 2-2]. Store the delivery client name in the variable $ RECEIVER. [Step 2-2] Timer setting and initialization An OS timer is set so that a software interrupt occurs one hour later. The number of blocks blkcnt, which is a variable, is initialized to zero. [Step 2-3] File pointer seek file 72 (file name / usr / spool / cachecast / tmp
/url.log) and seek the file pointer to the end of the file. A new temporary URL totaling buffer 8 with a file name of /usr/spool/cachacast/tmp/url.$RECEIVER.$blkcnt.log
Generate 0. After a certain time (for example, one hour), [s
Step 2-11]: An OS timer is set so as to execute the processing after step 2. [Step 2-4] Read one line Read one line from /usr/spool/cachecast/tmp/url.log. The data per line of this file is as follows as described above. Client computer name,--, [Date and time offset], "GET URL name HTTP / 1.0" Status code
Next, store the URL name in the variable $ URLBUF. Store the client computer name in a variable called $ CLIENT. [Step 2-5] Client exclusion Next, the character string included in the client name exclusion file 64 (cexclude.txt) specified by the argument when the cachecastw process is started is compared with the client computer name ($ CLIENT), and a matching pattern is found. If there is, cache delivery is not performed, and the process returns to [step 2-4]. For example, if the content of cexclude.txt is badboy others and the client computer name is badboy.foo.co.jp, cache delivery of the URL file object used by the client computer 8 is not performed. As a result, the administrator can suppress the delivery of the file object of the URL accessed by the specific client computer 8. [Step 2-6] Client Matching Next, the character string included in the client name matching file 66 (cpattern.txt) specified by the argument when the process cachecastw is started is compared with the client computer name, and even if there is at least one matching pattern If so, proceed with the cache file delivery of the URL file object. If not, the process returns to [step 2-4]. For example cpat
The content of tern.txt is goodboy friends and the client computer name is goodboy.foo.co.jp
If so, perform cache delivery of the URL file object used by this client. As a result, the administrator can explicitly permit only the file object of the URL accessed by the specific client computer 8 to be delivered. Client name match file 66 (cpatte
If the content of (rn.txt) is "*", cache delivery of the URL file object used by all client computers is performed. [Step 2-7] URL exclusion Next, the URL specified by the argument when starting the cachecastw process
The character string included in the exclusion pattern file 70 (exclude.txt) is compared with the URL name. If there is a matching pattern, cache delivery is not performed.
-4]. For example, the content of exclude.txt is playboy penthouse, and the URL name is http://www.playboy.foo.com/page.
If it is a gif, do not perform cache delivery. As a result, the delivery of an undesired URL of the client computer 10 is suppressed. [Step 2-8] Exclude delivery Check if the client computer name $ CLIENT matches the delivery client computer name $ RECEIVER,
If they match, cache delivery is not performed, so [st
ep2-4].

For example, if the delivery client computer name is cl
Let it be ient1. The first line of the following url.log is not cache-distributed because the client computer name matches the delivery client computer name. client1 [time date / time offset] “GET http: // n
aragw.sharp.co.jp/index.html HTTP / 1.0 ”200 1717 client2 [time and date offset]“ GET http: // n
aragw.sharp.co.jp/sharpcolor.gif HTTP / 1.0 ”200 1
The first line 370 indicates that a real access has occurred from the client computer (client1). For this reason, the file object of the corresponding URL must already be cached in the client cache file of the client computer (client1), and duplicate cache delivery can be prevented. [Step 2-9] URL matching pattern file 68 (pattern.tx
t) is compared with the URL name, and cache delivery is not performed if there is no matching pattern.
ep2-4]. URL matching pattern file 6
If the content of No. 8 is "*", the file objects of all URL names are cached and delivered. [Step 2-10] passed filtering
Write the URL to file 80 with the following file name,
It returns to [step2-4]. /usr/local/cachecast/tmp/url.$RECEIVER.$blkcnt.log With reference to FIG. 8, a description will be given of the delivery control execution process that occurs when the OS timer set in [step 2-3] interrupts the regular timer. . The delivery control execution process counts only the URL names from the access log file 14, creates a file in order of frequency, and performs delivery processing sequentially from the top. In the delivery process, the number of transfer bytes is accumulated, and the process is terminated when the specified hourly maximum transfer amount is exceeded. [Step 2-11] Scheduled interruption processing file 80 (/usr/local/cachecast/tmp/url.$RECEIV
ER. $ Blkcnt.log). Number of blocks ($ blkcn
t) is increased by one. Therefore, if the delivery client computer name is goodboy, /usr/local/cachecast/tmp/url.goodboy.1.log /usr/local/cachecast/tmp/url.goodboy.2.log / usr / local / cachecast / tmp / url.goodboy.3.log /usr/local/cachecast/tmp/url.goodboy.4.log; A file 80 with a file name of ;; is generated every hour. This file 80 is passed to the next processing process. [Step 2-12] Timer processing end file 80 (/usr/local/cachecast/tmp/url.$RECEIV
ER. $ Blkcnt.log). Also, the scheduled timer interrupt is set one hour later. The following process is an aggregator process
Start as a background process as ccwsum.

Referring to FIG. 9, the operation of tally child process ccwsum will be described after [step 2-13]. [Step 2-13] ccwsum URL appearance frequency order processing File name / usr / local / cachecast / tmp / url. $ RECEIVE
R. ($ blkcnt-1) Open the log file 80 and UR
L Sort names in order of appearance frequency, and URL in order of appearance frequency
Are arranged. For example, UNIX, sort, un
It can be realized by the following commands using iq and awk. cat /usr/local/cachecast/tmp/url.$RECEIVER.1.log \ │ awk '｛print $ 7 “” $ 10｝' \ ｜ sort ｜ uniq -c ｜ sort -n -r \ ｜ awk '｛print $ 2 “” $ 3｝ 'For example, the URL name and the number of bytes are output in the order of appearance frequency as follows. http://www.sharp.co.jp/index.html 2300 http://www.sharp.co.jp/a.gif 5423 ； ； This output is the URL frequency order temporary file 82 / usr / local / cachecast / tmp / url. $ RECEIVER. ($ blkcnt-
1) Write to .pop. Also returns the file pointer of this file to the beginning. With the above processing, the access log file 14
Are buffered and counted at regular intervals, and only those with a high appearance frequency are delivered.

Delivery client computer name ($ RECEIVER
) Is goodboy /usr/local/cachecast/tmp/url.goodboy.1.pop /usr/local/cachecast/tmp/url.goodboy.2.pop /usr/local/cachecast/tmp/url.goodboy .3.pop /usr/local/cachecast/tmp/url.goodboy.4.pop ； ;; [Step 2-14] Initialization unit URL frequency order temporary file 82 (/ usr / local / cachecast / t
Seek the file pointer at the beginning of mp / url. $ RECEIVER. ($ blkcnt-1) .pop). A variable representing the number of delivery child processes is set to webcnt, and webcnt is initialized to 0. The delivery child process will be described later. Next, a variable bytecnt representing the total amount of transfer bytes is initialized to zero. [Step 2-15] The number-of-processes comparison unit wait3 () Uses the system call to check the end of the child process. If the child process ends, webcnt is decremented by one. [Step 2-16] Maximum number of parallel processes check Number of delivery child processes (value of variable webcnt) and process 7
6 (cashecastw) Compares with the maximum number of parallel processes given by the argument at the time of startup. If the number of delivery child processes is equal to or less than the maximum number of parallel processes, the process proceeds to [step 2-17]. Otherwise, sleep () for about 1 second, sleep
When p () ends, [step 2-15] is executed again. [Step 2-17] URL size management section URL frequency order temporary file 82 (/ usr / local / cachecast / t
Read one line from mp / url. $ RECEIVER. ($ blkcnt-1) .pop). This is a file containing the delivery URL name and the number of bytes transferred. Therefore, the number of transfer bytes will be extracted from now on, by
Add the number of transfer bytes to the tecnt variable.

Bytecnt <= bytecnt + transfer byte count [step 2-18] transfer byte count check This bytecnt exceeds the maximum transfer byte count per hour given by the argument at the time of starting the process 76 (cachecastw), or one hour has elapsed. If so, end this process immediately. Otherwise, proceed to [step 2-19]. For example, if the current time is 13:40, the maximum number of bytes transferred per hour is 50 MB, and bytecnt reaches 52 MB, the process 76 is immediately terminated. As a result, cache delivery to the client computer 10 is suppressed so as not to exceed the maximum transfer byte count every hour. [Step 2-19] Delivery child process activation Client computer 1 to which the relevant URL is to be cached
URL to write to client cache file 32 of 0
Access child process (delivery child process) / usr / local / cac
Start hecast / webaccess as a background process. At this time, the cache status (status code)
Depends on the argument. If the file object is cached in the cache file 16, the options at the time of startup are as follows. / usr / local / cachecast / webaccess -p $ PORT $ RECEIV
ER $ URLBUF Add 1 to the value of the variable webcnt as the number of concurrent executions to control the number of parallel operations of the webaccess process.

When combined with webcnt <= webcnt + 1 [step 2-15], the number of executions of the delivery child process webaccess is always stored in webcnt, and is kept to be less than the maximum number of parallel processes. . Next, the process returns to [step 2-15].

Referring to FIG. 10, cache file 1
Delivery child process when file object is cached in 6 (/ usr / local / cachecast / webaccess)
The operation will be described. [Step 3-1] webaccess start In the client computer 10 to be cached, the client proxy server process 30 that manages the client cache file 32 is operating at the client port number specified by the argument when webaccss is started. It is assumed that the client proxy server process 30 is connected in multiple stages to the master proxy server process 12 running on the gateway computer 6 upstream thereof.

Accordingly, the URL access child process webacc
When ess is started, a request to obtain a file object of the specified URL is sent to the client proxy server process 30. The way to achieve this network access is
The same as described in [step 1-6], UNIX
Uses the socket mechanism that is the basis of the OS network function. This is the same as the method in which the client computer 8 makes a network connection to the gateway computer 6 to obtain a file object.

The delivery child process webaccess uses socket ()
Using the sd file descriptor, which is the socket obtained by the system call, the specified gateway computer 6
A connect () system call is generated between the machine name of the client and the TCP / IP client port number to establish a connection. [Step3-2] read / w of normal file using sd
Write GET method to get the file object of server computer 4 specified by $ URLBUF as in rite
And read the data.

That is, the GET URL name HTTP / 1.0 \ r \ n \ r \ n is written to this file descriptor sd as a line feed code represented by the hexadecimal code of \ r = 0x0t \ n = 0x0a. [Step 3-3] The client proxy server process 30 is a master with a cache of the gateway computer 6.
Since it is connected to the proxy server process 12 in multiple stages,
Further, the GET method is set to the master proxy server process 12
Send to Client proxy server process 30
Implements a normal proxy function, obtains the header and data part of the file object from the master proxy server process 12, and writes it in the client cache file 32. The operation of the client proxy server process 30 will be described later. [Step 3-4] The delivery child process (webaccess)
Next, data is read from sd until EOF (end of file). This data is the header and data part of the file object of the specified URL from the client proxy server process 30, but is not used in webaccess, so it is discarded and the process ends.

With the above operation, the gateway computer 6
Has been transferred to the client cache file 32 of the client proxy server process 30 of the client computer 10.

Next, the operation when the file object is not cached in the cache file 16 will be described. If it is not cached, [step1
-1], the child process cachecastwc performs the same operation as the child process cachecastw. cachecastwc is ca
The file to open is / usr / local / c compared to checastw
/ usr / local / cachecast / t instead of achecast / tmp / url.log
Same except for mp / url.c.log. cachecastwc is
Start ccwsum and ccwsum is / usr / local / cachecast / webac
Invoke cess to perform cache delivery operation.

The delivery control unit of the gateway computer 6 delivers the contents of the temporary cache file 20 to each client computer 10.

Referring to FIG. 11, from cachecastwc to ccws
Delivery child process started via um / usr / local / cac
Explain the operation of hecast / webaccess. [Step 4-1] webaccess start In the client computer 10 to be cached, the temporary cache update client proxy server process 34 that manages the client cache file 32 operates with the temporary cache port number specified in the argument when webaccess is started. It is assumed that As an example, the port number for the temporary cache is set to 8090. Here, the client cache file 32 stores the above [s
[step 3-1] is shared with the client proxy server process 30.

The temporary cache updating client pr
The oxy server process 34 is the upstream gateway computer 6
It is assumed that the multi-stage connection is established with the temporary cache updating master proxy server process 22 running on This temporary cache update master proxy server process 22
Is operating on port 10090. The master proxy server process 22 for updating the temporary cache
It is assumed that / usr / spool / cachecast / tmp / http / is used as a cache.

Therefore, when the URL access child process (delivery child process) webaccess is started, a request GET for acquiring the file object of the specified URL is sent to the temporary cache updating client proxy server process 34. Further, the temporary proxy cache updating proxy proxy process 34
y The connection to the server process 22 is made and / usr / spool
Temporary cache file 2 under / cachecast / tmp / http /
0 data is a temporary cache update client proxy
Transferred to server process 34.

The method for realizing this network access is as follows.
This is exactly the same as described in [step 3-1]-[step 3-3], and uses the socket mechanism which is the basis of the network function of the UNIX OS. This is the same as the method in which the client computer 8 makes a network connection to the gateway computer 6 to transmit a file object acquisition request.

The webaccess child process uses the sd file descriptor, which is the socket obtained by the socket () system call, to exchange the specified machine name of the gateway computer 6 with the TCP / IP temporary cache port number. , Connect () system call to establish a connection. [Step 4-2] GET method execution Next, similar to normal file read / write using sd
Write the GET method to get the file object of server computer 4 specified by $ URLBUF and write the data
read.

That is, the GET URL name HTTP / 1.0 \ r \ n \ r \ n is written to this file descriptor sd as a line feed code represented by the hexadecimal code \ r = 0x0d \ n = 0x0a. [Step 4-3] Data reading Since the temporary cache updating client proxy server process 34 is connected in multiple stages to the temporary cache updating master proxy server process 22 of the gateway computer 6, the temporary cache updating master proxy server is further executed. Send to process 22. The temporary cache updating client proxy server process 34 uses a normal proxy function to execute the temporary cache updating master proxy.
The header and data part of the file object are obtained from the oxy server process 22 and written into the client cache file 32. The operation of the temporary cache updating client proxy server process 34 will be described later. [Step 4-4] The delivery child process (webaccess)
Next, data is read from sd until EOF (end of file). This data is the header and data part of the file object of the specified URL from the client proxy server process 34 for updating the temporary cache.
It is not used in ess, so it is discarded and the process ends.

By the above operation, the file object of the URL temporarily cached in the temporary cache file 20 of the gateway computer 6 becomes the client cache file 32 of the client proxy server process 34 for updating the temporary cache of the client computer 10.
Was transferred to

Referring to FIG. 12, client computer 1
The operation of the client proxy server process 30 that performs reception control on the server 0 will be described. This is described in the prior art
Perform proxy server operation. The client proxy server process 30 is a proxy server with a cache that operates on the client computer 10, and relays the connection of the browser software 26 used by the user via the network layer. Also, a relay request from the cache delivery control unit 18 operating on the gateway computer 6 with the same port number is accepted. The connection destination is the upstream master proxy server process 12 (port number 10080).

The proxy setting of the browser software 26 is
Set to use port 8080 of localhost. The client proxy server process 30 performs the same process whether the request is a relay request from the browser software 26 or a relay request from the delivery control unit of the gateway computer.

The client proxy server process 30 sends the machine name of the upstream gateway computer 6 and the master proxy
y It has a table proxy.tbl that holds the port number of the server process 12, its connection state, and the last connection time.
For example, the following data is stored in proxy.tbl. master 8080 C 199611101130 The first field shows the machine name, and the second field shows the port number. The third field indicates the connection status (C is connection status, N is connection impossible). The fourth field indicates the time at which the connection state was determined. For example, 199611101130 is 19
It means 11:30 on November 10, 1996. [Step 5-1] GET method reception Client proxy server process 30 has port number 8
At 080, the apparatus enters a standby state to accept the service. [Step 5-2] Connection Establishment When a relay request for a specific URL is made to the port number 8080, a connection with the cache delivery control unit 18 is established. [Step 5-3] Thread Generation Upon receipt of this, the client proxy server process 30 generates a thread (child process) and entrusts the following processing, and returns to [step 5-1]. [Step 5-4] Cache check Start operation in the thread. The procedure on the requesting side (gateway computer 6) is the same as that described in [step 1-6] and the like. That is, the following acquisition request is transmitted to the client computer 10 as a line feed code represented by a hexadecimal code of \ r = 0x0d \ n = 0x0a. GET URL name HTTP / 1.0 \ r \ n \ r \ n Therefore, the client proxy of the client computer 10
The thread of the server process 30 checks whether a file object exists in the client cache file 32. URL is HTTP://www.sharp.co.jp/test/inde
If the URL is x.html, specifically, C: \ proxy \ cache \ http \ www.sharp.co.jp \ test \ index.htm
Check if there is a file called l. If there is no file, go to [step 5-5]. If there is a file, go to [step 5-5].
p5-7]. [Step 5-5] Connection establishment According to the data of proxy.tbl, if the connection is not possible within 3 minutes, the connection with the master proxy server process 12 is not established. If the connectable condition is satisfied, an attempt is made to establish a connection with the service port number 10080 of the master proxy server process 12 of the gateway computer 6. In addition, the connection status and time
Write and update in proxy.tbl. If connection cannot be established within 30 seconds, update the state of proxy.tbl. If the connection cannot be established, an error message is output and the processing ends. [Step 5-6] Data read and cache write Using any of the connections established in the above procedure,
A GET method is transmitted to any one of the master proxy server process 12, another proxy server process, and the server computer 4, and a file object including a header and a data portion is read. This is the client cache file 3
Write to 2. Specifically, C: \ proxy \ cache \ http \ www.sharp.co.jp \ test \ index.htm
Write a file object to l. The file object is also transferred to the side that issued the relay request. According to the HTTP specification, the file object creation time in the server computer 4 is stored in the client cache file 32 as Last-Mod.
In addition to being recorded in the ified: field, the file last modification time is recorded in the file system of the client computer 10 itself. This thread is now finished. [Step 5-7] Data length confirmation Cont is added to the header of the client cache file 32.
Check if ent-Length: is present. Content-Length:
If there is, branch to [step 5-8]. Content-Leng
If th: is not present, this is a dynamically generated temporary cache file so that the latest file object can be obtained from the network [step5-
5]. [Step 5-8] Validity period judgment The last modification time T1 of the file object of the corresponding URL is read and compared with the current time t. Cache expiration date in advance
EXPIRE is set in the client proxy server process.

If t-T1> EXPIRE, the cached file object has passed its expiration date, and the process proceeds to [step 5-5]. [Step 5-9] If the cache has not expired, the file object is read from the client cache file 32 and transferred to the side that issued the relay request.

With the above configuration, when accessed from the browser software 26, it functions as a normal proxy server process with a cache. As seen from the cache delivery control unit 18 of the gateway computer 6, the master proxy server process 12 is upstream of the client proxy server process 30. Therefore, the cache delivery control unit 18 simply accesses the cache file 16 of the master proxy server process 12 and issues a file object to the client proxy server process 30 by simply issuing the GET method. I have.

In addition, the client computer uses
A temporary cache update client proxy server process 34 that operates on the port number is running. The upstream connection destination is the temporary cache update master proxy server process 22 operating on the port number 10090 of the gateway computer 6. Other operations are the same as those of the proxy server described in [step 5-1] and thereafter, and thus description thereof will not be repeated.

The proxy server process for updating the temporary cache receives the web access request described in [Step 4-1] and thereafter, and receives the request for the master cache for updating the temporary cache on the upstream side.
y Access port 10090 of the server process 22 and access / usr / spool / cachecast / tmp / htt of the gateway computer.
By accessing p / www.sharp.co.jp / test / index.html, the data of the file object held in the temporary cache file 20 is transferred to the client cache file 32 C of the client proxy server process 34 for updating the temporary cache. : \ proxy \ cache \ http \ www.sharp.co.jp \ test \ index.htm
l can be copied to Therefore, the user can use the browser software 26 to http://www.sharp.co.jp
In a situation where /test/index.html is accessed and connection to the gateway computer 6 or connection to the server computer 4 is not possible, the file object in the temporary cache file 20 is sent to the browser software 26. Therefore, even a dynamically generated file object can be used in an environment disconnected from the network.

In this distributed file system 2, the same file object is simultaneously delivered to a plurality of client computers 10 by accessing the server computer 4 via the gateway computer 6, and a specific client computer 8 is used. By periodically accessing a specific file object of the server computer 4 via the gateway computer 6 mechanically, the specific file object can be delivered to a plurality of client computers 10.

As a result, for example, a user of a certain client computer 8 can intentionally forcibly deliver file object data deemed necessary to a user of another client computer 10. For example, if the manager's client computer 8 accesses information necessary for sales, materials required for sales are naturally stored as a cache in the subordinate client computer 10.

In the distributed file system 2, the reception control unit 28 of the client computer 10 detects the free area capacity of the disk device at fixed time intervals, and uses up to a certain percentage of the free area as the client cache file 32. can do. Thereby, the maximum value of the cache capacity of the client cache file 32 is dynamically set, and when it exceeds this, old file objects and unused file objects are erased, and control is performed so that the free area is kept within the maximum value. it can.

As a result, for example, the free area of the disk device of a certain client computer 10 can be mostly used as the client cache file 32, and when another application starts consuming the disk device, the cache area of the client cache file is reduced. The user does not need to set the cache size.

In the distributed file system 2, the cache delivery control unit 18 of the gateway computer 6 creates an access log of the transmission data at regular time intervals, and transmits the transmission list in which the appearance frequency is added to the access log to the reception control of the client computer 10. It can also be transmitted to the unit 28 and presented to the user.

Thus, an overview of the user's popularity information on the file object can be obtained.

In the distributed file system 2, the reception control unit 28 of the client computer 10 can designate a plurality of gateway computers other than the gateway computer 6 as upstream connection destinations. If it cannot be connected to any of them, an attempt is made to directly connect to the server computer 4, and if it is not possible to connect any further, a control method of taking out data from the client cache file 32 can be adopted.
Thus, even if one of the gateway computers is malfunctioning or a network disconnection accident occurs, data can be extracted from the client cache file 32.

In the distributed file system 2, the reception control unit 28 of the client computer 10 can also create a reception access log at regular intervals, and submit a totalized reception list to the user. As a result, the user can be notified of the outline of the information on the received file object. The client computer 10 can selectively access the file object.

Referring to FIG. 1, the cache delivery control unit 18 of the gateway computer 6 transmits a GET method to the reception control unit 28 of the client computer 10. Therefore, the cache delivery control unit 18 receives the file object from the reception control unit 28. This file object is for the purpose of copying the file object held in the cache file 16 of the gateway computer 6 to the client cache file 32 of the client computer 10, and is not used by the cache delivery control unit 18. Occurs. Therefore, the reception control unit 2 of the client
In No. 8, the generation of useless traffic can be suppressed by not transmitting the substance of the file object to the GET method from the cache delivery control unit 18.

In FIG. 1, a cache delivery control unit is installed in the client computer 10, an access log is generated in the client proxy server process 30, and if the cache delivery control unit refers to the access log, the client proxy server Process 30 can also have a cache delivery function. If one gateway computer 6 can support only about 10 client computers 10 to be cached,
It is also possible to arrange a plurality of client computers that receive cache delivery under the client computer 10. This is a kind of repeater.

In FIG. 1, the cache delivery control unit 18 of the gateway computer 6 performs cache delivery while monitoring the access log file 14.
Any file other than the access log file 14 may be used as long as the file describes a URL. You can also store a URL list in a specified file, and then use it to cache and deliver daily batches.

Referring to FIG. 13, client computer 10c receiving the file object is disconnected from high-speed internal network 38, and uses a low-speed network 99 such as a telephone line at a destination using a device such as a wired or wireless modem. It is assumed that the server computer 4 is connected to the server computer 4 via a server. In this case, by using the client cache file 32 to obtain a high hit rate, it can also be used as an acceleration device that apparently reduces the transfer time of the low-speed network 99.

In the distributed file system 2, a reception control unit 28 is mounted on a notebook personal computer, connected to an internal network 38 at work or the like, communicates with the gateway computer 6, and operates at a low speed network 99 at a destination. To communicate with the server computer 4. High-speed internal network 38
Is composed of a 10 Mbps (Mega bits / second) Ethernet or wireless communication network.

Referring to FIG. 14, client computer 1
A large-capacity (about 600 MB) medium 100 such as a removable magneto-optical disk can be used as the 0b client cache file 32. Thus, by carrying only the large-capacity medium 100, the client computer 10c having the reception control unit 28 can use the client cache file 32 as a client cache file 32, thereby realizing high-speed access even in the client computer 10c.

Further, by applying the distributed file system 2 to digital satellite broadcasting or the like, the client proxy server process 30 receives information (file object) in one direction from a satellite or the like via radio, and only when necessary, the master proxy server process. It is also possible to perform two-way communication with the process 12 through a wire to obtain a file object.

According to the distributed file system 2 as described above, the file object accessed by the user of another client computer 8 can be transferred to its own client computer 10.
In the client cache file 32. Therefore, the cache hit rate can be improved. Moreover, even when the internal network 38 is congested or when the client computer 10 is used in the low-speed network 99, a comfortable access speed can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a distributed file system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a gateway computer.

FIG. 3 is a diagram illustrating file object transfer of a gateway computer.

FIG. 4 is a diagram illustrating file object transfer of a gateway computer.

FIG. 5 is a block diagram illustrating a configuration of a cache delivery control unit.

FIG. 6 is a flowchart illustrating a process of a process cachecastd.

FIG. 7 is a flowchart illustrating a process of a process cachecastw.

FIG. 8 is a flowchart illustrating an interrupt process in a process cachecastw.

FIG. 9 is a flowchart illustrating a process of a process ccwsum.

FIG. 10 is a flowchart illustrating processing of a process webaccess.

FIG. 11 is a flowchart illustrating a process of a process webaccess.

FIG. 12 is a flowchart illustrating processing of a client proxy server process that performs reception control on a client computer.

FIG. 13 is a diagram illustrating a client computer connected to a low-speed network.

FIG. 14 is a diagram illustrating a client computer having a removable large-capacity medium.

FIG. 15 is a block diagram showing a configuration of a conventional WWW system.

[Explanation of symbols]

2 distributed file system 4 server computer 6 gateway computer 8,10 client computer 12 master proxy server process 14 access log file 16 cache file 18 cache delivery control unit 20 temporary cache file 22 temporary proxy update master proxy server process 24, 26 browser software 28 reception control unit 30 client proxy server process 32 client cache file 34 temporary client update client proxy server process

Claims (19)

[Claims] A server computer for receiving an access request and transmitting a file object corresponding to the access request; a plurality of client computers; a gateway computer; and the gateway computer comprising the server computer and the plurality of client computers. A communication line for connecting to each other via a computer, wherein each of the plurality of client computers is a client cache file for temporarily holding the file object; and Sending the access request to obtain an object,
A first file object receiving unit for receiving the file object and writing the file object in the client cache file, wherein the gateway computer has a cache file for temporarily holding the file object, and the server computer An access log file for holding reception record information when receiving the file object from, and connected to the access log file, receiving the access request from each of the plurality of client computers,
The file object is obtained from the cache file or the server computer, and transmitted to the client computer that transmitted the access request and the reception record information and the client computer selected by a predetermined selection method, and the client computer selected as necessary. File object distribution means for writing to the cache file and writing the reception record information to the access log file. 2. The file object distribution means,
Receiving the access request from each of the plurality of client computers, acquiring the file object from the cache file or the server computer, transmitting the file object to the client computer that transmitted the access request, and, if necessary, the cache file And a file object obtaining proxy unit for writing the reception record information to the access log file, and connected to the access log file, among the plurality of client computers, according to the reception record information and a predetermined selection method. File object access request transmitting means for transmitting the access request to the selected client computer, wherein the first file object receiving means transmits the access request from the file object access request transmitting means. Receiving a Seth request comprises means for transmitting to said file object acquisition proxy means, distributed file system according to claim 1. 3. The distributed file system according to claim 1, wherein the client cache file is a removable storage medium. 4. The file object access request transmitting unit transmits the access request for acquiring the file object in the order of appearance frequency of the file object name recorded in the reception record information. Distributed file system. 5. The file object access request transmitting unit transmits the access request for acquiring the file object by excluding the file object name recorded in the reception record information including a predetermined character string. 3. The distributed file system according to claim 2, wherein 6. The file object access request transmitting unit according to claim 2, wherein the file object access request transmitting unit transmits the access request to a client computer other than the client computer that has acquired the file object through the reception proxy unit, based on the reception record information. Distributed file system as described. 7. The file object access request transmitting unit transmits the access request for acquiring the file object for which the client computer has made an access request, including a predetermined character string, based on the reception record information. The distributed file system according to claim 2, wherein 8. The gateway computer further includes a holding determination unit connected to the cache file for determining whether or not the file object is stored, wherein the file object access request transmitting unit is configured to store the file object. Connected to the judging means, and only when the file object is held in the cache file,
3. The distributed file system according to claim 2, further comprising means for controlling transmission of the access request for acquiring the file object. 9. The file object distribution means,
3. The distributed file system according to claim 2, further comprising means for controlling transmission of said file objects in parallel within a predetermined number of parallel deliveries. 10. The gateway computer is connected to the file object distribution means, and a temporary cache file for temporarily storing a dynamic file object among the file objects; Dynamic file object transmitting means for receiving an access request for acquiring the dynamic file object, reading the dynamic file object from the temporary cache file, and transmitting the read dynamic file object to the client computer that transmitted the access request The reception record information further includes information indicating whether the file object received from the server computer is the dynamic file object, and the cache file is a dynamic file object among the file objects. Temporarily holding file objects that do not exist, the file object distribution means further includes means for writing to the temporary cache file if the file object obtained from the server computer is the dynamic file object, The file object access request transmitting unit is connected to the access log file, refers to the reception record information, and if the file object acquired from the server computer is the dynamic file object, the plurality of client computers A dynamic file object access request transmitting means for transmitting the access request for acquiring the dynamic file object to a client computer selected according to the reception record information and a predetermined selection method; If the file object obtained from the server computer, which is connected to the access log file and refers to the reception record information, is the non-dynamic file object, the reception record information and the predetermined Static file object access request transmission means for transmitting the access request to obtain the non-dynamic file object to the client computer selected according to the selection method, wherein each of the plurality of client computers, A requester connected to the dynamic file object access request transmitting means for transmitting the access request, receiving the dynamic file object, and writing the dynamic file object in the client cache file; Distributed file system according to claim 2. 11. A server computer for receiving an access request and transmitting a file object corresponding to the access request, a plurality of client computers for transmitting the access request and receiving the file object, and a gateway computer A gateway computer used in a distributed file system including a communication line for interconnecting the server computer and the plurality of client computers via the gateway computer, wherein the file object is temporarily stored. A cache file for receiving the file object from the server computer; and an access log file for holding reception record information when receiving the file object from the server computer. Access request,
Obtain the file object from the cache file or the server computer, transmit the received record information and the client computer selected by a predetermined selection method to the client computer, and if necessary, write the received record information to the cache file. A file object distributing means for writing the access log file. 12. The file object distribution means receives the access request from each of the plurality of client computers, acquires the file object from the cache file or the server computer,
A file object acquisition proxy unit for transmitting the access request to the client computer, writing the cache file as necessary, and writing the reception record information to the access log file, and connecting to the access log file 12. The file object access request transmitting means for transmitting the access request to a client computer selected according to the reception record information and a predetermined selection method among the plurality of client computers. Gateway calculator. 13. The file object access request transmitting unit transmits the access request for acquiring the file object in the order of appearance frequency of the file object name recorded in the reception record information.
The gateway computer according to claim 12. 14. The file object access request transmitting unit excludes the file object name recorded in the reception record information including a predetermined character string,
The gateway computer according to claim 12, wherein the access request for acquiring the file object is transmitted. 15. The file object access request transmitting unit transmits the access request to a client computer other than the client computer that has acquired the file object through the reception proxy unit based on the reception record information. The described gateway calculator. 16. The file object access request transmitting unit transmits the access request for acquiring the file object for which the client computer has made an access request, including a predetermined character string, based on the reception record information. The gateway computer according to claim 12, wherein: 17. Connected to the cache file,
The file object access request transmitting unit further includes a holding determination unit for determining whether the file object is held, and the file object access request transmitting unit is connected to the holding determination unit, and the file object is held in the cache file. Only if
13. The gateway computer according to claim 12, further comprising means for controlling transmission of the access request for acquiring the file object. 18. The gateway computer according to claim 12, wherein said file object acquisition proxy means further includes means for controlling transmission of said file objects in parallel within a predetermined parallel delivery number. 19. A temporary cache file connected to the file object distribution means for temporarily storing a dynamic file object among the file objects, and the dynamic file from each of the plurality of client computers. Dynamic file object transmitting means for receiving an access request for obtaining an object, reading the dynamic file object from the temporary cache file, and transmitting the read dynamic file object to the client computer that transmitted the access request. The reception record information includes information indicating whether the file object received from the server computer is the dynamic file object, and the cache file includes a non-dynamic file object among the file objects. Temporarily holding the file object, wherein the file object distribution means further includes a means for writing to the temporary cache file if the file object acquired from the server computer is the dynamic file object; The request transmission unit is connected to the access log file, refers to the reception record information, and if the file object obtained from the server computer is the dynamic file object, the request transmission unit includes, among the plurality of client computers, Dynamic file object access request transmission means for transmitting the access request for acquiring the dynamic file object to the client computer selected according to the reception record information and a predetermined selection method; and the access log file Connected, referencing the reception record information, if the file object obtained from the server computer is the non-dynamic file object, select the plurality of client computers according to the reception record information and a predetermined selection method. 13. The gateway computer according to claim 12, further comprising: a static file object access request transmitting unit configured to transmit the access request for acquiring the non-dynamic file object to the client computer.