JP2010152783A - Load distribution access system, object holding device, client device, and method and program therefor in distributed file system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem in which load distribution takes time since an object server queries the next object server for whether it can transfer a request based on a list, there is no method for determining a receiving destination of the request when all object servers reject receipt of the request, and when an object server which holds a replica is changed, all the object servers holding the replica of the list must be individually updated. <P>SOLUTION: The load distribution access system includes an object mapping information management means; a load value evaluation means; and a load value comparison means. When a client transmits a request to an object server, position information of all the object servers holding the replica is stored in the request, and when the object server transfers the request, the request is transferred to the other object server while storing the load value therein. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a load distribution access system, an object holding device, a client device, a method thereof, and a program thereof in a distributed file system. In particular, the present invention relates to a load distribution access system, an object holding device, a client device, a method thereof, and a program thereof that can transfer a request to an optimal server at a higher speed without managing the access load centrally. Is.

  Non-patent document 1 and non-patent document 2 are examples of systems that store files in a distributed manner. The distributed file system described in Non-Patent Document 1 and Non-Patent Document 2 includes a client device, a name resolution unit (metaserver device), and a data storage unit (storage device).

  The file may be stored in the data storage unit as it is, or a file obtained by dividing the data may be stored as an object in a plurality of data storage units. In addition to the file system metadata, the name resolution means holds files, objects constituting the files, and mapping information between the objects and the storage apparatus. When stored in units of files, mapping information between files and storage devices is held. When the client device accesses the data, it is necessary to inquire the name resolution means about the object information corresponding to the data portion to be accessed.

  Further, as one method for improving the reliability of data, there is means for storing replicas (copies) of objects in a plurality of storage devices. When the client device reads an object, it may be read from any one object. At this time, as a method of distributing the reading load of the data storage unit, a method of managing the access status to the data storage unit with a name resolution unit or the like can be considered.

  However, with this method, the part that manages the access status becomes a single-point-of-failure (SPOF) and becomes a performance bottleneck, and the load that takes into account the conditions of the software and hardware environment of the data storage means There was a problem that it could not be dispersed.

  A method for solving this problem is described in Patent Document 1. In the technique described in Patent Document 1, the load is monitored by each object server (storage device), and it is determined whether or not a read request from the client device (hereinafter, the request means a read request) is accepted. If it is determined that the request is not accepted, the request is transferred to another object server. At this time, each server holds a destination object server list to be transferred. When the next object server is selected from the list, it is first inquired whether the request can be transferred to the object server, and if there is a reply, the request is transferred. In this way, the problems caused by the single centralized management method are solved.

  However, with this method, the object server searches the next object server from the list, and further inquires whether the request transfer is possible to the next object server before transferring the request. is there.

In addition, if all of the transfer candidate object servers refuse to accept the request, there is no way to determine which object server will eventually accept the request, so the request can be forwarded without being forwarded. There is a problem that continues to be. Furthermore, when there is a change in the object server holding the replica, the list of all object servers holding the replica must be updated separately, resulting in a large overhead.
JP 2003-256390 A D. Nagle, et al., “The Panasas ActiveScale Storage Cluster: Delivering Scalable High Bandwidth Storage”, In Proceedings of SC2004, November 2004, Pittsburgh, Pennsylvania. Sage A. Weil et al., “Ceph: A Scalable, High-Performance distributed File System”, In Proceedings of 7th OSDI06, November 2006, Boston, Massachusetts.

  The first problem is that load distribution takes time. The reason is that the transfer candidate object server is searched from the list of each object server, and it is transferred after confirming whether the object server can accept the request. As the number of objects held increases, the list size also increases, and the search time also increases.

  The second problem is that if all transfer candidate object servers refuse to accept the request, there is no way to determine which object server will ultimately accept the request. The reason is that there is no means for knowing an index representing the magnitude of the load when inquiring whether the request can be accepted from the transfer candidate object server. Patent Document 1 and Non-Patent Documents 1 and 2 do not describe a processing method when all transfer candidate object servers refuse to accept a request, and the load on one of the object servers becomes low and can be accepted. Will continue to inquire whether transfer is possible.

  The third problem is that the list update overhead accompanying the change of the replica holding information is large. The reason is that each object server holds a position information list of object servers holding the same replica. As the number of objects and the number of replicas increase, the update overhead increases.

[Object of invention]
An object of the present invention is to provide a load distribution access system, a method thereof, and a program thereof that can perform load distribution at high speed.

  Another object of the present invention is to provide a load balancing access system and method for transferring a request to an object server having the smallest load or discarding a request when any transfer candidate object server has a high load, and a program thereof. There is to do.

  Still another object of the present invention is to provide a load distribution access system and method, and a program thereof that can reduce processing overhead when information of object servers holding the same replica is updated.

  The object holding device of the present invention determines a load evaluation unit that calculates a load value, and determines whether to accept a request based on the load value. If the request is not accepted, the load value is stored in the request, and If the request is transferred based on information on another object holding device stored in the request, and the request is not accepted by all object holding devices, the load value is the highest among the requests. A load value comparison unit that performs any one of an operation of transferring the request to a low object holding device and an operation of discarding the request, and accepts the request when the request is received once; It is provided with.

  The client device according to the present invention includes an object mapping information holding unit that holds correspondence information between an object and an object holding device that stores the object, and object holding device information obtained from the object mapping information holding unit. And a client application execution means for storing and transmitting.

  The load distribution access system according to the present invention is a load distribution access system comprising an object holding device and a client device, wherein the object holding device calculates a load value, and requests based on the load value. If the request is not accepted, the load value is stored in the request, and the request is transferred based on the information of another object holding device stored in the request. Then, when the request is not accepted by all the object holding devices, one of the operation of transferring the request to the object holding device having the lowest load value in the request and the operation of discarding the request If the request received once is received again, Load value comparison means for accepting an est, wherein the client device holds object mapping information holding means for holding correspondence information between an object and an object holding device storing the object, and the object mapping information holding means Client application execution means for storing the obtained object holding device information in the request and transmitting it.

  The load distribution access system of the present invention is a load distribution access system comprising an object holding device and a client device, wherein the object holding device calculates load time for reading an object from a load value, The object read time is compared with the deadline time, and it is determined whether or not the request is accepted based on the comparison result. If the request is not accepted, the request is sent to the object holding device that has not yet received the request. A load value comparing means for discarding the request and notifying the client device that the request has been discarded when it is determined that the request is unacceptable. The client device stores the object and the object. With the object holding device Object mapping information holding means for holding information, client application execution means for storing the object holding device information obtained from the object mapping information holding means in the request, and dead for calculating the deadline time of the request object Line time calculating means.

  The load distribution access system of the present invention is a load distribution access system comprising an object holding device, a client device, and a metadata holding device, wherein the object holding device calculates a load value; Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, When the request is transferred and the request is not accepted by all the object holding devices, the request is transferred to the object holding device having the lowest load value among the requests, and the request is discarded. The request that has been received and executed once. Load value comparing means for accepting the request when received again, and the metadata holding device comprises object mapping information holding means for holding correspondence information between the object and the object holding device storing the object The client device comprises client application execution means for storing the object holding device information obtained from the object mapping information holding means in the request and transmitting it.

  The load distribution access system according to the present invention is a load distribution access system comprising an object holding device and a client device, wherein the object holding device is based on load evaluation means for calculating a load value, and on the load value. To determine whether to accept the request, and if not, store the load value in the request and transfer the request based on the information of another object holding device stored in the request If all the object holding devices do not accept the request, either the operation of transferring the request to the object holding device having the lowest load value among the requests or the operation of discarding the request If the request received once is received again, An object mapping comprising: a load value comparing means for accepting the request; and a location information providing means for providing location information, wherein the client device holds correspondence information between the object and the object holding device storing the object. Information holding means, client application execution means for storing and transmitting the object holding device information obtained from the object mapping information holding means in the request, and position information providing means for providing position information. Features.

  The object holding method of the present invention includes a step of calculating a load value, and determining whether or not to accept the request based on the load value. If not accepted, the load value is stored in the request, and the request is stored in the request. The step of transferring the request based on information of another stored object holding device, and the object holding device having the lowest load value among the requests when all the object holding devices do not accept the request A process for transferring the request to the server, a process for discarding the request, and a step of accepting the request when the object holding device receives the request again. It is characterized by having.

  The operation control method for a client device according to the present invention includes a step of holding correspondence information between an object and an object holding device storing the object, and requesting object holding device information obtained by using the holding step. And storing and transmitting.

  The load distribution access method of the present invention is a load distribution access method used in a load distribution access system comprising an object holding device and a client device, wherein the object holding device calculates a load value, It is determined whether or not to accept the request based on the load value. If the request is not accepted, the load value is stored in the request, and the request is based on the information of another object holding device stored in the request. And when the request is not accepted by all object holding devices, the step of transferring the request to the object holding device having the lowest load value among the requests, and the step of discarding the request Step to perform one and receive once If the request is received again, the step of accepting the request is executed, and the client device holds correspondence information between the object and the object holding device storing the object, and the holding step And storing the object holding device information obtained by using the request in the request.

  The load distribution access method of the present invention is a load distribution access method used in a load distribution access system comprising an object holding device and a client device, wherein the object holding device calculates an object read time from a load value. The calculation step is compared with the object readout time and the deadline time, and it is determined whether or not to accept the request based on the comparison result. If not accepted, the request has not been received yet. If the request is transferred to the object holding device and the request is determined to be unacceptable, the request is discarded and the client device is notified of the discard, and the client device The object storing the object A step of holding correspondence information with the object holding device, a step of storing the object holding device information obtained from the object mapping information holding means and transmitting it in the request, and a step of calculating a deadline time of a request object , Is executed.

  The program of the present invention determines a load value calculation process and whether to accept a request based on the load value. If not accepted, the load value is stored in the request and stored in the request. Based on the information of another object holding device, and when the request is not accepted by all object holding devices, the object holding device having the lowest load value among the requests is sent to the object holding device. A process for executing a process for transferring a request and a process for discarding the request; and a process for accepting the request when the object holding device receives the request again. It is made to perform.

  In addition, the program of the present invention stores a process for holding correspondence information between an object and an object holding apparatus storing the object, and object holding apparatus information obtained by using the holding process in a request. And transmitting the data in a computer.

  The program of the present invention is a program to be executed by a computer of a load distribution access system that controls operations of the object holding device and the client device, and the object holding device calculates the load value, and the load It is determined whether to accept the request based on the value. If not, the load value is stored in the request, and the request is determined based on the information of another object holding device stored in the request. When the request is not accepted by all object holding devices, either the processing to transfer the request to the object holding device with the lowest load value among the requests, or the processing to discard the request The process to execute or the request received once And a process of accepting the request if received, and a process of holding correspondence information between the object and the object holding device storing the object in the client device, and using the holding step And processing for storing the object holding device information obtained in this way in the request and transmitting it.

  The program of the present invention is a program executed by a computer of a load distribution access system that controls operations of an object holding device and a client device, and the object holding device calculates an object read time from a load value. The object read time and the deadline time, determine whether to accept the request based on the comparison result, and if not, the object holding device that has not yet received the request in the request And when the request is determined to be unacceptable, the request is discarded and the client device is notified that the request has been discarded. The containing object Processing for holding correspondence information with the holding device, processing for storing and transmitting the object holding device information obtained from the object mapping information holding means, processing for calculating the deadline time of the request object, Is executed.

  The first effect is that the load can be distributed at high speed according to the present invention. The reason is that in the present invention, since the location information of the object server holding the replica is stored in the request, the search for the transfer candidate object server when the object server transfers is the minimum stored in the request. This is because limited information is sufficient. Another reason is that the present invention transfers a request without determining whether the transfer destination object server can accept the request.

  The second effect is that according to the present invention, even when all the transfer candidate object servers have a high load, the request can be transferred to the object server having the smallest load. The reason is that in the present invention, the object server stores and transmits information indicating the load level of each object server in the request. Therefore, according to the present invention, even if the load is unacceptable in all object servers, the load values of the requests are compared, the request is transferred to the object server having the smallest load value, and the request can be discarded. it can.

  The third effect is that according to the present invention, the list update overhead accompanying the change of the replica holding information is small. This is because in the present invention, the object server information storing the object and its replica is managed on the client side.

  An object is data held by each object server. An object may be data itself accessed by a client, or may be data obtained by dividing data accessed by a client. Each object holds replicas (copies) in a plurality of object servers to improve reliability.

Next, the best mode for carrying out the invention will be described in detail with reference to the drawings.
Referring to FIG. 1, the first embodiment of the present invention includes a client 100 in which an application is operating, object servers 101a and 101b that hold objects, and a transmission path 102 that connects the client and the object server. .

  The client 100 includes a client application 10, an object mapping information management unit 11, and a request transmission / reception unit (not shown).

  The object servers 101a and 101b include load value comparison units 20a and 20b, object access processing units 21a and 21b, load evaluation units 22a and 22b, and object holding units 23a and 23b.

Each of these means generally operates as follows.
The client application 10 operates on the client 100 and reads necessary data from the object server.

  The object mapping information management unit 11 holds correspondence information between an object and an object server in which the object is stored. In response to a request from the client application 10, the object mapping information management unit 11 stores position information on the object server in which the corresponding part of the object is stored return.

  The request transmission / reception unit transmits a request from the client application 10 to the object server designated by the client application 10.

  The load value comparison units 20a and 20b compare the load value stored in the request with the load value of its own object server, and determine whether to accept the request.

  The object access processing units 21a and 21b receive the object access request.

  The load evaluation units 22a and 22b calculate the load values of the object access processing units 21a and 21b.

  The object holding units 23a and 23b hold objects.

  The overall operation of this embodiment will be described in detail with reference to flowcharts and drawings.

  First, the operation of the client will be described. When the client application 10 accesses an object stored in the object server, first, the object mapping information management unit 11 is inquired of the location information of the object server in which the object to be accessed is stored. The object mapping information management unit 11 returns all the location information of the object server in which the object is stored. As shown in FIG. 2, the client application 10 stores the object request information, its own client location information, and all the object server location information in the request, and transmits the request to any one of the object servers.

  Next, the operation of the object servers 101a and 101b will be described with reference to the flowchart of FIG. Hereinafter, the object server that has received the request is referred to as its own object server, and other object servers are referred to as other object servers.

  A request from the client is received (step S100). The load evaluation unit determines whether or not the load value of the own object server is stored in the request (step S101). In the case of no, since the received request is the first, the process proceeds to a process for determining whether to accept the request. If yes, the request has already been received and the load value is stored and transferred. This request has been transferred in the processing step S108 of the other object server, which means that the load value is the lowest among the object server groups holding the object requested by the client. Therefore, the request is accepted without judging the load value. The load evaluation unit calculates the load value (step S102). Based on the load value obtained from the load evaluation unit, it is determined whether or not the load value comparison unit accepts the request (step S103).

  If the request is not accepted as a result of the determination in step S103, the load value is stored in the load value field of the request as shown in FIG. 3 (step S104). When the load value is stored in the request, it is confirmed whether the load values of all object servers are stored in the request (step S105). If all are stored (Yes in step S105), an object server having the lowest load value is found, and it is confirmed whether or not it is the own object server (step S107).

  In the process of step S105, when there is an object server for which the load value is not yet stored in the request (in the case of no in step S105), the request is transferred to the object server (step S106). In the process of step S107, if the own object server has the lowest load value (yes in step S107), it is determined that the request is received by the own object server, and the request is passed to the object access processing unit (step S109). When the load value is the lowest in the other object server (in the case of no in step S107), the request is transmitted to the other object server. Here, the final request processing method when the load of all the object servers holding object replicas is high is that the object server with the lowest load accepts the request, but the request is discarded. It may be replaced.

Next, the effect of this embodiment will be described.
In this embodiment, when the own object server is heavily loaded, when a request to the own object server is transferred to another object server, it can be transferred immediately with reference to the information in the request, so load distribution is executed at high speed. be able to.

  Further, in the present embodiment, by storing the load value in the transfer request, even if any object server has a high load, the object server having the lowest load value accepts the request or discards the request. , Etc. can be executed.

  In the present embodiment, when the object server holding the replica is changed, only the information of the object mapping information management unit of the client need be changed. Therefore, it is possible to reduce the processing overhead when changing the replica holding information.

[Second Embodiment]
Next, a second embodiment of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 5, the second embodiment of the present invention is different from the first embodiment in that the object mapping information management unit is held in the meta server 103 instead of the client 100.

  The processing procedure of the second embodiment of the present invention is the same as the processing procedure of the first embodiment except that the client application 10 inquires the object mapping information management unit 11 via the transmission path 102.

Next, the effect of 2nd Embodiment of this invention is demonstrated.
Since the object mapping information is centrally managed by the meta server 103, the processing overhead when changing the object mapping information can be reduced.

[Third Embodiment]
Next, a third embodiment of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 6, in the third embodiment of the present invention, a deadline calculation unit 12 is added to the client 100 as compared with the first embodiment (FIG. 1), and the load on the object servers 101a and 101b is further increased. The difference is that the value comparison units 20a and 20b are replaced with deadline determination units 24a and 24b.

  The overall operation of the present exemplary embodiment will be described in detail with reference to flowcharts and drawings.

  The client application 10 causes the deadline calculation unit 12 to calculate the object read deadline time and stores it in the request. The request at this time is obtained by adding the deadline time to the information in FIG.

  Next, the processing procedure of the object servers 101a and 101b when receiving a request will be described with reference to FIG. First, a request is received from a client (step S200). Next, the time required to read the object is calculated from the load value of the object server (step S201), and it is determined whether or not the object can be provided within the deadline time stored in the request (step S202).

  If it is possible (yes in step S202), the request is accepted as it is, and the request is passed to the object access processing unit (step S207). If it is not possible (no in step S202), an object unacceptable flag is set in the request (step S203). The transfer request at this time is the one in which the load value portion in FIG. 3 is replaced with the object unacceptable flag. Next, it is confirmed whether or not all object acceptance impossible flags are set in the request (step S204).

  If all the object unacceptable flags of the request are set (yes in step S204), the client application is notified that the request cannot be accepted, and the request is discarded (step S206). If no value is set in all the object unacceptable flags of the request (no in step S204), the request is transferred to an object server for which no flag is set (step S205).

Next, the effect of this embodiment will be described.
In the first embodiment, if the load on the object server is low, a request that does not meet the time required by the client is accepted and the load is increased unnecessarily. On the other hand, according to the third embodiment, by referring to the deadline time stored in the request at the object server, the request is discarded if the deadline time cannot be met in all the object servers holding the replica. It is possible to avoid an unnecessary increase in the load on the object server.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 8, the fourth embodiment of the present invention is different from the first embodiment in that the client 100 has the position information providing unit 13 and the position information providing units 25a and 25b are object servers. 101a and 101b are different. Here, the position information is position information (network coordinates) on the network, physical position (GPS), or the like. Therefore, the position information of this embodiment is a parameter different from the client position information shown in FIG.

Next, a processing procedure according to the fourth embodiment of the present invention will be described.
The client stores the location information together with the request. The request at this time is obtained by adding position information to the content of the request shown in FIG.

  The object server that has received the request considers the distance between the client and its own object server in addition to the load value when determining whether to accept the request. The other processing procedure is the same as the processing procedure of the first embodiment.

  The effect of the fourth embodiment is that a request can be transferred to an object server that allows a faster response.

[Example]
Next, the operation of the best mode for carrying out the present invention will be described using specific examples.

  An operation in which a certain object server receives a request from the client application, transfers the request, and finally transmits the request to the object server having the lowest load value will be described in detail.

  Assume that there are three object servers (respectively, object servers A, B, and C), and that the files accessed by the client application are stored in the three object servers as objects. Here, there are three object servers, but the present invention can be applied if there are two or more object servers. There is no limit to the number of clients. The transmission path may be Fiber Channel, InfiniBand, etc., but here is Ethernet (registered trademark). The load index may be a CPU usage rate, a network bandwidth usage rate, a disk request queue length, power consumption, and the like, but here it is a disk request queue length. The criterion for determining whether or not to accept the request is whether or not the request queue length of the disk is 10 or more. As another example of the load standard, an evaluation formula that outputs the load value by combining the loads of the CPU, the disk, the network, and the like may be used. In this evaluation formula, each load ratio may be weighted and added.

  In order to access the file, the client application first inquires the object mapping information management unit about the location information of the object server holding the file as an object. Since the files are stored in the object servers A, B, and C, the client application obtains the IP address of each object server from the object mapping information management unit. The client application stores the object request information (file ID, file offset value, etc.), the client address, and the address of each object server in the request, and transmits the request to the object server. Here, it is assumed that the object server A is selected at random.

  Assume that the object server A receives the request and calculates the load value to be 15. In this case, the object server A does not accept the request, stores its own load value in the request, and transfers it to the object server that does not yet store the load value. Here, it is assumed that the data is randomly transferred to the object server C.

  It is assumed that the object server C receives the request and calculates the load value, which is 30. Similarly to the object server A, the object server C stores its own load value in the request and transfers it to the object server B.

  It is assumed that when the object server B receives the request and calculates the load value, it is 20. In this case, since the load value threshold is exceeded in all the object servers, C forwards the request to A having the smallest load value.

  The object server A receives the request again. However, since the load value is stored in the request, it is determined that the load value is the lowest among the object server groups holding the replica, and the request is accepted.

  In the above case, the load distribution takes the longest time. If there is an object server whose load value is smaller than the threshold value, the load is distributed at a higher speed.

  The present invention can be applied to an access load distribution application in a distributed file system including a plurality of object servers and a plurality of clients, particularly in a distributed file system storing a plurality of object replicas.

It is a block diagram which shows the structure of 1st Embodiment of this invention. It is a figure which shows the attribute field of the request which a client transmits to an object server in 1st Embodiment. It is a figure which shows the attribute field of a request when an object server transfers a request to another object server in 1st Embodiment. It is a flowchart which shows operation | movement of 1st Embodiment. It is a block diagram which shows the structure of 2nd Embodiment of this invention. It is a block diagram which shows the structure of 3rd Embodiment of this invention. It is a flowchart which shows operation | movement of 3rd Embodiment. It is a block diagram which shows the structure of 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Client application 11 Object mapping information management part 12 Deadline calculation part 13 Location information provision part 20a, 20b Load value comparison part
21a, 21b Object access processing unit 22a, 22b Load evaluation unit 23a, 23b Object holding unit 24a, 24b Deadline determination unit 25a, 25b Location information providing unit 100 Client 101a, 101b Object server 102 Transmission path 103 Meta server

Claims (18)

Load evaluation means for calculating a load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, When the request is transferred and the request is not accepted by all the object holding devices, the request is transferred to the object holding device having the lowest load value among the requests, and the request is discarded. Load value comparison means for executing any one of the operations, and receiving the request once received again,
An object holding device comprising: The object holding device according to claim 1, further comprising: position information providing means for providing position information. Load evaluation means for calculating the object readout time from the load value;
The object read time is compared with the deadline time, and it is determined whether to accept the request based on the comparison result. If not, the request is sent to the object holding device that has not yet received the request in the request. Load value comparing means for discarding the request and notifying the client device that the request has been discarded.
An object holding device comprising: Object mapping information holding means for holding correspondence information between an object and an object holding device storing the object;
Client application execution means for storing the object holding device information obtained from the object mapping information holding means in a request and transmitting it;
A client device comprising: The client apparatus according to claim 4, further comprising deadline time calculation means for calculating a deadline time of the request object. The client apparatus according to claim 4, further comprising position information providing means for providing position information. A load balancing access system comprising an object holding device and a client device,
The object holding device is
Load evaluation means for calculating a load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, When the request is transferred and the request is not accepted by all the object holding devices, the request is transferred to the object holding device having the lowest load value among the requests, and the request is discarded. Load value comparing means for executing any one of the operations and receiving the request when the request received once is received again,
The client device is
Object mapping information holding means for holding correspondence information between an object and an object holding device storing the object;
Client application execution means for storing the object holding device information obtained from the object mapping information holding means in the request and transmitting it;
A load balancing access system characterized by comprising: A load balancing access system comprising an object holding device and a client device,
The object holding device is
Load evaluation means for calculating the object readout time from the load value;
The object read time is compared with the deadline time, and it is determined whether to accept the request based on the comparison result. If not, the request is sent to the object holding device that has not yet received the request in the request. Load value comparing means for discarding the request and notifying the client device that the request has been discarded when it is determined that the request is unacceptable.
The client device is
Object mapping information holding means for holding correspondence information between an object and an object holding device storing the object;
Client application execution means for storing the object holding device information obtained from the object mapping information holding means in the request and transmitting it;
Deadline time calculating means for calculating the deadline time of the request object;
A load balancing access system characterized by comprising: A load balancing access system comprising an object holding device, a client device, and a metadata holding device,
The object holding device is
Load evaluation means for calculating a load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, When the request is transferred and the request is not accepted by all the object holding devices, the request is transferred to the object holding device having the lowest load value among the requests, and the request is discarded. Load value comparing means for executing any one of the operations and receiving the request when the request received once is received again,
The metadata holding device is
Comprising object mapping information holding means for holding correspondence information between an object and an object holding device storing the object;
The client device is
A load balancing access system comprising: client application execution means for storing the object holding device information obtained from the object mapping information holding means in the request and transmitting it. A load balancing access system comprising an object holding device and a client device,
The object holding device is
Load evaluation means for calculating a load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, When the request is transferred and the request is not accepted by all the object holding devices, the request is transferred to the object holding device having the lowest load value among the requests, and the request is discarded. Load value comparison means for executing any one of the operations and receiving the request once received again,
Position information providing means for providing position information,
The client device is
Object mapping information holding means for holding correspondence information between an object and an object holding device storing the object;
Client application execution means for storing the object holding device information obtained from the object mapping information holding means in the request and transmitting the information;
Position information providing means for providing position information;
A load balancing access system characterized by comprising: Calculating a load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, Forwarding the request;
If the request is not accepted by all object holding devices, one of the processing of transferring the request to the object holding device having the lowest load value in the request and the processing of discarding the request is executed. And steps to
Accepting the request if the object holding device has received the request once again;
An object holding method characterized by comprising: Holding correspondence information between the object and the object holding device storing the object;
Storing and transmitting object holding device information obtained using the holding step in a request;
An operation control method for a client device, comprising: A load balancing access method used in a load balancing access system comprising an object holding device and a client device,
The object holding device is
Calculating a load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, Forwarding the request;
If the request is not accepted by all object holding devices, the step of transferring the request to the object holding device having the lowest load value among the requests and the step of discarding the request When,
Performing the step of accepting the request once received once again,
The client device is
Holding correspondence information between the object and the object holding device storing the object;
Storing and transmitting the object holding device information obtained using the holding step in the request;
A load balancing access method characterized in that A load balancing access method used in a load balancing access system comprising an object holding device and a client device,
The object holding device is
Calculating an object readout time from a load value;
The object read time is compared with the deadline time, and it is determined whether to accept the request based on the comparison result. If not, the request is sent to the object holding device that has not yet received the request in the request. If the request is determined to be unacceptable, the step of discarding the request and notifying the client device of the discard is performed.
The client device is
Holding correspondence information between the object and the object holding device storing the object;
Storing the object holding device information obtained from the object mapping information holding means in the request and transmitting it;
Calculating the deadline time of the request object;
A load balancing access method characterized in that Processing to calculate the load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, Processing to forward the request;
If the request is not accepted by all object holding devices, one of the processing of transferring the request to the object holding device having the lowest load value in the request and the processing of discarding the request is executed. Processing to
A process of accepting the request when the object holding device has received the request once again;
A program that causes a computer to execute. Processing for holding correspondence information between an object and an object holding device storing the object;
A process for storing the object holding device information obtained using the holding process in a request and transmitting the request;
A program that causes a computer to execute. A program to be executed by a computer of a load balancing access system that controls operations of an object holding device and a client device,
In the object holding device,
Processing to calculate the load value;
Determine whether to accept the request based on the load value, if not, store the load value in the request, based on the information of another object holding device stored in the request, Processing to forward the request;
When all the object holding devices do not accept the request, processing for transferring the request to the object holding device with the lowest load value in the request and processing for discarding the request When,
A process of accepting the request when the request received once is received again,
In the client device,
Processing for holding correspondence information between an object and an object holding device storing the object;
Processing to store and transmit object holding device information obtained using the holding step in the request;
A program that executes A program to be executed by a computer of a load balancing access system that controls operations of an object holding device and a client device,
In the object holding device,
A process of calculating the object readout time from the load value;
The object read time is compared with the deadline time, and it is determined whether to accept the request based on the comparison result. If not, the request is sent to the object holding device that has not yet received the request in the request. When the request is determined to be unacceptable, the request is discarded and the client device is notified that the request has been discarded.
In the client device,
Processing for holding correspondence information between an object and an object holding device storing the object;
Processing for storing and transmitting the object holding device information obtained from the object mapping information holding means in the request;
Processing to calculate the deadline time of the request object;
A program that executes

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