JPH09212377A - Remote file system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To construct a remote file system capable of shortening the response time to a remote file service request, preventing the loss of data even when a computer system is suddenly stopped and quickly restoring the damage of a local file system. SOLUTION: A remote file service request transmitted from another computer through a network is stored in a non-volatile memory 33 and a response to the request is returned without executing practical I/O processing. In the stored state of data included in the request in the memory 33, the processing of the request is executed by a local file system 37 so that remote file service interrupted by a sudden stop of the computer is recovered by using the contents stored in the memory 33 and the service request outputted immediately before the stop is restarted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a remote file system capable of coping with a temporary failure.

[0002]

2. Description of the Related Art A remote file system using a network is NFS developed by San Micro, Inc.
(Network File System), AFC (Andrew File System) developed by Carnegie Mellon University in the United States, and the like. These remote file systems can make files that are distributed across the network appear to be at hand.

A feature of NFS, which is used almost standardly as a network file system at the present time, is that a server that provides file system services is stateless. This means that the server does not save client-dependent state, which allows the server to recover quickly from a crash.

However, since the server has no state,
Whenever the client makes a request to the server, it must send all the information to the server so that the requested operation can be performed. In addition, the server must make the request from the client synchronously. This is because the server may crash after replying to the client that it has processed the request, and if the request cannot be completely processed, the client may have inconsistent processing.

[0005]

On the other hand, in UFS (UNIX file system) which is a file system for a local disk such as UNIX which is an industry standard OS, normal file operation is limited to copy processing on the memory. Since the synchronization processing to the disk is not performed, the processing can be performed at high speed. So in NFS,
Since the request is always processed synchronously, there is a drawback that the response time is slow compared to the local file system.
There is a problem that the speed of the disk greatly affects the performance when the processing is concentrated.

The present invention has been made in view of the above circumstances, and by performing high-speed processing without performing synchronization processing to a disk, the response time to a remote file system request is shortened, and an unexpected stop occurs. Realizes a highly reliable remote file system service that does not lose data in the event of an accident, and can quickly recover damage to the local file system in the event of an unexpected stop, and The object is to provide a remote file system that can perform file operations completely.

[0007]

In a computer system that performs a remote file service via a network, the remote file system of the present invention is a local file system for managing a disk provided in the computer system and another via a network. The remote file service request sent from the computer is stored in the non-volatile memory and the remote file service request is stored in the non-volatile memory, and the input / output processing of the request is delayed to perform the actual input / output processing. The remote file management unit that returns a response to the remote file service request without issuing the command, and the remote file service interrupted by the unexpected stop of the computer are recovered using the above non-volatile memory, and the service request immediately before the stop is restarted. Service recovery department Characterized in that it.

Further, a log file system for recovering the damage of the file system due to the temporary failure of the computer by logging the operation for changing the file system is further provided, and the log written by the log file system is stored in the nonvolatile memory. It is also characterized by writing a log in and saving damage to the local file system due to an unexpected stop of the computer.

Each of the computer systems described above is under the control of a communication unit for exchanging information with other computer systems, a remote file system unit for processing a service request received via the communication unit, and a remote file system management unit. A non-volatile memory in which the service request is stored, and a file update information table in which a history of what service request from another computer system has been processed under the control of the remote file system management unit, A file system management unit that creates and manages a file system on a disk using memory, and the above non-volatile memory and file update information table during the process of restarting the computer system after an unexpected stop And a service recovery unit that terminates the processing of the remote file service request of

The file update information table includes a file handle indicating a file to be operated, an operation command for the file, an offset indicating the position of the file, a memory size for the operation, a file name argument and a nonvolatile memory for write data. Storage location in
It is characterized in that at least one piece of status information indicating that it is being processed or has been processed is displayed as a flag.

[0011]

In the above-mentioned structure, the remote file service request transmitted from another computer via the network is stored in the non-volatile memory, and the request is returned without performing actual input / output processing. The stored file is stored in the non-volatile memory, the request is processed by the local file system, the remote file service interrupted by the unexpected stop of the computer is recovered using the non-volatile memory, and the service request just before the stop. It is characterized by restarting.

As a result, it becomes unnecessary to copy unnecessary data between the non-volatile memory and the normal memory, the response of the remote file service is returned at high speed, and the actual input / output processing is realized at high speed. it can.

Further, high reliability can be realized by the service recovery unit recovering the interruption of the remote file service due to the unexpected stop of the computer. In addition, since the local file system uses the non-volatile memory, it is possible to highly reliable both the remote file service and the request to the local file system generated inside the computer system.

As described above, the response time to the remote file service request is shortened by responding to the remote file service request without issuing the actual input / output, and the remote file service request is stored in the non-volatile memory. It is possible to provide a highly reliable remote file service in which data is not lost in the event of an unexpected stop by storing the file and repairing the file system based on the log written in the nonvolatile memory.

On the other hand, when the local file system responds to the remote file service request without issuing the actual input / output, and the local file system uses the non-volatile memory as a cache, an unexpected stop occurs. The damage can be recovered at high speed, and both the remote file service and the request to the local file system generated from inside the computer system can be made highly reliable.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, reference numerals 1 and 3 are computer systems, which are connected via a network 2.

The computer system 3 includes a communication unit 31, a remote file system management unit 32, a non-volatile memory 33,
The file update information table 34, the memory 35, the disk 36, the local file system management unit 37, the service recovery unit 38 and the like are included.

The communication unit 31 includes hardware for exchanging information with another computer system 1, and the remote file system 32 is software for processing a service request received via the communication unit 31. Non-volatile memory 3
In 3, the service request is stored under the control of the file system management unit 32.

Further, the file update information table 34 stores what kind of service request from another computer system 1 has been processed under the control of the remote file system management unit 32.

The file system management unit 37 includes a memory 3
5 is used to create a file system on the disk 36 and manage it. When the computer system 3 is restarted after an unexpected stop, the service recovery unit 38 uses the non-volatile memory 33 and the file update information table 34 to complete the processing of the remote file service request being processed. is there.

A specific example of the non-volatile memory 33 is N
There is VRAM (Non-Volatile Random Access memory) and the like. It can be used in the same way as a normal memory, and even if the power supply is stopped, the stored content is not reduced by its own backup power supply for a certain period of time. Delay time-consuming disk I / O, instead of NVR
By storing data in AM, a high-speed response can be returned. Also, in case of unexpected system down, NVR
Since the AM never loses data, high reliability can be realized.

The file system management unit 37 manages the file system created on the disk 6. Only the part different from the normal file system management will be extracted and described with reference to the flowchart shown in FIG.

FIG. 3 is a flowchart showing the macroscopic flow of processing by the file system management unit 37. The file update information table 34 stores service requests that the remote file system management unit 32 has received so far and that have not been reflected in the disk 36.

An example of the entry structure of the file update information table 34 is shown in FIG. Normally, a service request to the remote file system is sent by the file handle 1.
2, operation command 13, offset 14, size 28,
It is composed of a pointer 29 to an argument or data and each element of the processing state 30.

The file handle 12 indicates a file to be operated, the operation command 13 is an operation (read, write, etc.) to be performed on the file, the offset 14 is a file position, and the size 28 is an operation. As for the memory size to be performed, the pointer 29 to the other argument or data is the storage location of the argument (file name or the like) or the write data in the non-volatile memory 33, and the processing state 30 is processing or being processed. Indicates the status of something.

FIG. 3 shows a flow of operation of the embodiment of the present invention. When a service request actually arrives from the computer system, the request arrives at the same time as the non-volatile memory 3
3 (step 15).

Next, the correctness of the operation is checked (step 16). If this is a remote file system,
This is because it is necessary to correctly return whether or not the requested operation can be performed so that the processing is consistent.

At this time, first, the file update information table 34 can be inspected and the operation can be performed (for example, the already deleted file cannot be further deleted).
If it is not there, the file system management unit 37 is inquired to confirm that the operation can be performed.

The file system management section 37 responds by referring to the data on the disk 36 as to whether or not the operation can be performed (steps 17, 18, 19, 20). Then, the arrived request is registered in the file update information table 34.

However, if other operations have not been completed for the data of the file to be operated, it waits until the operation is completed. While waiting, the file update information table 34
The processing state is recorded as "waiting". When other operations are completed, change to the "unprocessed" state. At this time,
In the case of a data amount operation such as writing, the address where the data is stored in the non-volatile memory 33 is put in the argument portion of the file update information table 34.

Next, the fact that the request has been processed is returned as a response (step 21). Since the requested processing can be executed (inspected in step 16) and the data necessary for processing is stored in the non-volatile memory 33 (steps 17-20), the processing may be completed. Then, the file system management unit 37 is notified that the processing is actually performed, and the arrived request is processed (step 22).

In the case of the operation of changing the configuration of the file system or updating the data of the file, the file system management section 37 processes the notified request.
Since the remote file system has already returned a response, it may be synchronous processing (I / O processing is executed immediately) or asynchronous processing (I / O processing is delayed).

Normally, the file system management unit 37 uses the memory 35 as a high speed cache when a large amount of data is used for a write operation. However, in the present invention, the data already stored in the non-volatile memory 33 is used as it is. The storage location is shown in the file update information table 34.

As a result, unnecessary data copy does not occur between the non-volatile memory 33 and the normal memory, and high-speed input / output processing can be performed. In the case of the operation of referring to the file system or the information of the file, if the file system is not changed, or if the data of the file is not changed and only the reference is performed, the file system management unit 37 performs the processing as usual. At this time, since the remote file system management unit 32 may be operating, the file system management unit 3
7 performs the processing shown in FIG.

FIG. 4 is a diagram showing the flow of file reference processing by the file system management unit 37. First, the data of the file to be referred to is the file update information table 34.
Is checked (step 25), and if there is not enough, the contents of the file update information table 34 and the memory and disk information are referred to (step 26), and a response is returned (step 28). If not, it refers to the data cached in the memory and the data on the disk (step 27) and returns a response.

It should be noted that the explanation is returned to the original (FIG. 3) and the file update information table 34 is referred to first because the remote file system management unit 32 has not issued the actual input / output, but has already returned the response. This is because the above operation is stored in the file update information table 34.

First, the end of processing is recorded in the file information update table (step 23). The file system management unit 32 ends the input / output operation, and the operation result is the disk 3
When reflected in 6, the entry responding to the file information update table 34 is processed. Next, a response indicating that the remote file system request cannot be processed is returned (step 24).

Next, the operation when the computer system 1 is suddenly stopped due to a temporary hardware failure or the like will be described. When the computer system 1 is restarted, it is detected from the contents of the non-volatile memory 33 that the previous system stop unexpectedly occurred and there is a remote file service being processed.

At this time, the service recovery unit 38 performs processing for restarting the interrupted service. In the file update information table 34, the actual input / output operation is performed one by one for the entries other than the processing status “completed” in the order of registration.

The data for that purpose is not lost and is recorded in the file update information table 34 because it is stored in the non-volatile memory 33 even in case of an unexpected stop. At this time, regarding the entry in the "waiting" state,
A response indicating the completion of processing is returned to the original computer system. The processing status is changed to “completed” from the processing completed.

After all the entries in the file update information table 34 have been processed, the normal remote file service is started. As described above, even if the computer system unexpectedly stops due to the operation of the service recovery unit and the operation on the file update information table 34,
It is possible to process a remote file service request that has already returned a response but is not actually reflected in the disk, and return a response to the request that was being processed immediately before the stop.

FIG. 5 is a block diagram showing another embodiment of the present invention. In the figure, reference numerals 4 and 5 are computer systems, which are connected via a network 6.

The computer system 5 includes a communication section 51, a remote file system management section 52, a non-volatile memory 53,
File update information table 54, memory 55, disk 56, file system management unit 57, service restoration unit 5
8 and a log file system 59.

The communication unit 51 includes hardware for exchanging information with another computer system 1, and the remote file system 52 is software for processing a service request received via the communication unit 51.

Service requests are stored in the non-volatile memory 53 under the control of the file system management unit 52. Further, the file update information table 54 stores what kind of service request from another computer system 1 has been processed under the control of the remote file system management unit 52.

The file system management unit 57 has a memory 5
5 is used to create a file system on the disk 56 and manage it. When the computer system 3 is restarted after an unexpected stop, the service recovery unit 58 uses the non-volatile memory 53 and the file update information table 54 to complete the processing of the remote file service request being processed. is there.

The log file system 59 is for recovering the damage to the file system at a high speed due to a temporary failure of the computer system by logging the operation of making changes to the file system as a history.

The operation will be described below, but only the part different from the embodiment shown in FIG. 1 will be extracted and described to avoid duplication. When a remote file service request is processed in a normal state, the following process is performed in addition to the process of the embodiment shown in FIG.

That is, of the remote file service requests, before the file system management unit 57 actually issues the input / output relating to the file system configuration change such as file creation and deletion to the disk 56, the log file system The operation contents are transmitted to 59.

The log file system 59 records the contents in the non-volatile memory 53 as a log. When the input / output recorded in the log file system 59 ends, the file system management unit 57 notifies the log file system 59 that the input / output ends. The log file system 59 puts the corresponding input / output log in the commit state.

On the other hand, when the computer system is suddenly stopped and restarted, the following process is performed in addition to the process of the first embodiment shown in FIG. The service recovery unit 58 cancels the operations shown in the uncommitted log in the order from newest to oldest.

These logs are in the process of input / output processing immediately before the down, and it is not known whether the processing is actually reflected in the disk. Therefore, the disk state is once restored (cancel).

After that, the uncommitted logs are processed in the order from oldest to newest. As a result, it is possible to quickly recover the damage to the file system caused by the unexpected stop.

By adopting the log file system,
The safety of the file system is improved, and unlike the normal log file system, since the log is only written to the non-volatile memory 53 instead of the disk 56, the input / output processing is not deteriorated at high speed.

Although the remote file service can be continued without losing the request even if the computer system is suddenly stopped, the operation of the file system generated inside the computer system cannot be guaranteed.

The embodiment described below improves on that point. As the system configuration, the example shown in FIG. 1 is used.
The difference is the operation of the remote file system management unit 32 and the file system management unit 37.

In a normal file system, the memory 35 is used as a cache. The file system management means 37 in the embodiment of the present invention is the nonvolatile memory 33.
Is used as a cache.

As a result, the cache for modifying and referring to the file data is not lost due to an unexpected stop, so the file system on the disk 36 is not damaged and the reliability is higher.

The file system is damaged by an unexpected computer system stop. During normal processing, there is data cached in the memory and not reflected in the disk 36, and the data is lost due to the system stop.
It occurs because the state of the disk 36 becomes a state in the middle of processing.

As described above, if the nonvolatile memory 33 is used as a cache, such file system damage will not occur. The data of the file cached in the non-volatile memory 33 may be performed in the same manner as a normal file system delays and reflects the cache on the disk 36.

Next, the remote file system management unit 3
The process by 2 will be described. Most of the processing is the same as the embodiment diagram shown in FIG. The only difference is the steps 21, 22, and 23 of the flowchart showing the operation. In the embodiment shown in FIG. 1, the service request response is returned, and then the request is actually reflected in the disk 36 and the processing is terminated.

It is modified as shown below. That is, first, the arrived request is processed (step 21).
At this time, the actual processing is performed by the file system management unit 37, but the input / output to / from the disk 36 is not issued, and as described above, the nonvolatile memory 33 is used as the cache to perform the requested file operation. .

Then, the end of processing is recorded in the file update information table (step 22), and a response indicating the completion of processing (step 23) is returned. As described above, unlike the embodiment shown in FIG. 1, the file system management unit 37 first performs the actual processing of the operation, but since the actual input / output operation to the disk 36 does not occur, the conventional remote file Responses can be returned faster than the system.

Next, how to process the file system operation on the disk generated inside the computer system will be explained. The file operation that occurs inside the computer system means that an application or the like running on the computer system uses the file system on the disk.

In the embodiment shown in FIG. 1, it is difficult to maintain the consistency with the remote file service request which is not reflected in the disk 36 and which is held by the remote file system management unit 32.

However, as described above, since the file system management unit 37 actually processes the remote file service request and returns a response, the above-mentioned consistency problem does not occur.

Therefore, the file system management unit 37 may process the file operation generated inside the computer system. By doing so, the remote file service request and the file operation request generated inside the computer system can be processed without contradiction.

[0068]

As described above, according to the present invention, a remote file service request transmitted from another computer via a network is stored in a non-volatile memory, and a request reply is sent without performing actual input / output processing. The request is processed by the local file system while the data contained in the request is stored in the non-volatile memory,
It is characterized by recovering the remote file service interrupted by the unexpected stop of the computer by using the above nonvolatile memory and restarting the service request immediately before the stop, without performing the synchronization processing to the disk, By performing high-speed processing, the response time for remote file system requests is shortened, and a highly reliable remote file system service that does not lose data in the event of an unexpected stop is realized. It is possible to construct a remote file system capable of quickly recovering damage to the local file system in the case of the stop of the above, and capable of completely executing the file operation during the processing.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing an entry structure of a file information update table used in the embodiment shown in FIGS.

FIG. 3 is a flowchart showing a processing procedure of each of the above embodiments.

FIG. 4 is a flowchart showing a processing procedure of each of the above embodiments.

FIG. 5 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

1, 3 ... Computer system, 2, 6 ... Network, 3
1, 51 ... Communication unit, 32, 52 ... Remote file system management unit, 33, 53 ... Non-volatile memory, 34, 54
... file update information table, 35, 55 ... memory, 3
6, 56 ... Disk, 37, 57 ... File system management unit, 38, 58 ... Service recovery unit, 59 ... Log file system.

Claims (5)

[Claims] 1. A computer system for performing remote file service via a network, the computer system comprising: a local file system for managing a disk provided in the computer system; and a remote computer transmitted from another computer via the network. Non-volatile memory for storing file service requests and remote file service requests are stored in the above non-volatile memory, and the input / output processing of the requests is delayed to execute the remote file service without issuing the actual input / output processing. The remote file management unit for returning a response to the request, and the service recovery unit for recovering the remote file service interrupted by the unexpected stop of the computer by using the nonvolatile memory and restarting the service request immediately before the stop Remote file Ill system. 2. A log file system for recovering damage to the file system due to a temporary failure of a computer by logging an operation for changing the file system, and a log written by the log file system is stored in the nonvolatile memory. The remote file system according to claim 1, wherein the log is written in the file to recover the damage to the local file system due to the unexpected stop of the computer. 3. The computer system comprises a communication unit for exchanging information with another computer system, a remote file system unit for processing a service request received via the communication unit, and a control for the remote file system management unit. A non-volatile memory in which the above service request is stored, and a file update information table in which a history of what service request from another computer system has been processed under the control of the remote file system management unit is stored. , A file system management unit that creates and manages a file system on a disk using memory, and a process using the above nonvolatile memory and file update information table when the computer system is restarted after an unexpected stop And a service recovery unit for terminating the processing of the remote file service request on the way. The remote file system according to claim 1, wherein: 4. The file update information table includes a file handle indicating a file to be operated, an operation command for the file, an offset indicating a position of the file, a memory size indicating an operation range, an argument such as a file name, or write data. 4. The remote file system according to claim 3, wherein at least one of the storage location in the non-volatile memory and the status information indicating that the processing is in progress or has been processed is flagged. 5. A remote file service request transmitted from another computer via a network is stored in a non-volatile memory, the request is answered without performing actual input / output processing, and the data included in the request is stored. The request is processed by the local file system while being stored in the non-volatile memory, the remote file service interrupted by the unexpected stop of the computer is recovered using the non-volatile memory, and the service request just before the stop is restarted. A network file system characterized in that