JPS5913783B2 - Duplicate file method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a duplex file system that includes a first file group and a second file group that is a copy 20 of the first file group in order to prevent failures of the first file group. The present invention relates to a method 25 for restoring the contents of the file group to normal after the computer system recovers from a failure due to a cause unrelated to the file group, due to processing interruption at the time of the failure.

In the duplex file method in electronic computer systems,
A first file group and a second file group that is a copy of the first file group are provided in order to prevent failures of the file group, and when an update request is made to one file, both files are Two corresponding files in the group are updated, and even if one file causes a read/write failure, processing continues on the other file that is unrelated to the failure, increasing system reliability. .

35) When the electronic computer is stopped due to the occurrence of a failure in the first file group unrelated to the second file group, all input/output commands being read/written at the time of the stop are not guaranteed.

If a file in the first file group or second file group is in the middle of being read at the time of this stop, the contents of the file will not be destroyed, and the computer can be restarted as is with respect to the file.

However, if a file in the first file group or second file group is being updated by writing when the computer is stopped, the contents of the file will be destroyed because the update is in progress. Therefore, an update storage means is provided for each file to indicate that it is being updated, and if one of the corresponding files in both file groups is being updated at the time of failure, the file that was being updated can be stored in the other file. It was restored with a file. Furthermore, if the computer is stopped when the update of one file is completed and before the update of the corresponding file of the other file is started, the contents of the corresponding files will be different. Therefore, a level storage means is provided for each file to indicate the update level, and if the levels of corresponding files in both file groups are different at the time of failure, a file with a newer update level is copied to a file with an older update level. There is. Conventionally, requests for updating or reading each file in a file group were received independently, but it is now possible to divide a large amount of complexly related information and store it in separate files depending on the nature of the information. For example, file A
, file B and file C, and at some point it is necessary to update file A and file B8 at the same time. At another time, if files B and C need to be updated at the same time, the files that are to be updated at once in response to one request are grouped, and the files are updated in groups. If a computer stops due to a failure while updating a group, even if a file in the group has been updated, the group is still being updated, and all files belonging to that group will be updated. The data in the file has been destroyed, and with the conventional method of controlling updates on a file-by-file basis, it has been impossible to restore the file group so that the computer can be restarted. The present invention aims to overcome the above-mentioned drawbacks and includes a first file group and a second file group which is a copy of the first file in order to prevent damage to the first file group. It is provided with an update storage means indicating that an update is in progress and a level storage means indicating an update level, so that when the computer recovers from a failure due to a cause unrelated to the above file groups, the corresponding files in both file groups are stored at the time of occurrence of the failure. If one file was being updated, the file that was being updated is restored using the other file, and if both corresponding files in both file groups were not being updated at the time of the failure, the new file at the update level is restored. Due to the duplex file system of computer systems, which copies files to files with an older update level, when updating at least two files in a group, files are being updated in a group. A group control means is provided that sets/resets a display indicating that the group has been updated in a predetermined storage means in response to each file, and at the time of failure recovery, the file that was being updated as a group is restored with the file that was not being updated as a group. By this,
Even if nine computers stop due to a failure while updating files in groups, it is now possible to restore the above file group.

This invention will be explained in detail below with reference to the drawings. The figure is a configuration diagram of an embodiment of the duplex file system based on the present invention.

In the figure, 11 is the first file group, 21 is the second file group, 12 to 15 are the files, and 22 to 25 are the files.
is the copied file of files 12 to 15, and 12
a~15a and 22a~15a are update storage means, 12b~
15b and 22b to 25b are level storage means.

31 is an update means, 41 is a group control means, 51 is a file recovery means, 52 is a reading means for display stored in the update storage means, 53 is a restoration means, and 54 is a copying means.

Files 12 to 15 in the first file group 11 are the files 22 to 2 in the second file group 21 that have been copied.
The update storage means 12a to 15a and the update storage means 2 each display a message indicating that each file is being updated.
2a to 25a, and level storage means 12b to 15b and level storage means 22b to 25b which can display the update level as an additional update.

When the file updating means 31 decides to update a certain file, it selects one of the file groups, and the group control means 41 selects one file group.
to notify.

The group control means 41 sets an update in progress display in the update storage means of the file to be updated and notifies the update means 31 of the file. If there are a plurality of files to be updated at this time, the files are treated as a group and an indication that the file is being updated is set in the update storage means of all files belonging to the selected group. Upon receiving the notification from the group control means 41, the updating means 31 starts updating each file of the file group for which the group control 41 has set the display of being updated.
When the updating of all files in the file group for which the updating display is set is completed, the group control means 41 is notified, and the group control means 41 updates the contents of the level storage area and updates each of the files that have been updated. Resets the display being updated in the update storage means.

The groove control means 41 notifies the update means 31 which resets all the update displays, and the update means 31 requests the group control means again to set the update displays for the remaining file group. Thereafter, the group update display is set, the group file is updated, the level storage area is updated, and the group update display is reset in the same manner, and the updating of the first file group and the second file group is completed.

Here, there are several methods in the level storage area, such as storing an update serial number, v storing the number of update generations, and D storing the date and time when an update request occurred. If a failure occurs in a file in the first file group or second file group during the above processing, the updating means 31 discards the file in which the failure has occurred and enters single-lung operation, or separately updates the file area. We are currently taking two options: secure the facilities and operate with double files.

If the system is stopped due to a failure unrelated to the first file group and the second file group, the various input/output devices that were in the process of reading or writing at the time of the failure are no longer guaranteed from the time the failure occurred.

If the file is in the middle of being read, the file from which it is being read is generally not destroyed, so it can be read again once the failure occurs. However, if a failure occurs during the update, the file being updated will be destroyed, with parts that have already been updated and parts that have not been updated yet. Also 2
If the system is stopped due to a failure after completing the update of one of the multiplexed files and before starting the update of the other, the update levels of files that should be the same will be different. The file duplication means 51 performs the processing necessary for restarting a system that has stopped due to a failure, according to the following procedure. The reading means 52 reads the update storage means 12a, 22a and the level storage means 12b, 22b of the file 12 in the first file group and the file 22 in the second file group which is a copy thereof, and first stores it in the update storage means. Check whether update display is set.
If the updating display is set on one side, the file to which the updating display is set has been destroyed, so the copying means 54 restores it using the other file. Also, if the updating display is not set for either file,
Next, the updated levels in the level storage means 12b and 22b are compared. If the update levels are different, the copying means 54 copies the new file of the update level to the old file of the update level. Thereafter, the file recovery means 51 sequentially reads the update storage means and level storage means of the corresponding files in both file groups, and makes each file recoverable from the failure. As explained above, when using a computer system that adopts the duplex file method, when updating at least two files in a group of files,
A group control means is provided to set/reset the display indicating that a file is being updated on a group basis, and at the time of failure recovery, the file that was being updated in the group is restored with the file that was not being updated in the group. It has become possible to restore duplicated files in which each file forms a group that differs in time and generates an update request.

In the above description, the existing update storage means was used as the update storage means for storing the display during update, but it is also possible to separately provide a group update storage means that can set the display during group update.

According to this method, in which the group update means is separately provided in addition to the update storage means, the file recovery means 51 can somewhat easily recover a file for which there is an indication that group processing is in progress. For example, for a file for which there is a group update display but the update has not started, the file recovery process is completed by simply resetting the group update display.

[Brief explanation of the drawing]

The figure is a configuration diagram of an embodiment of the duplex file system based on the present invention. In the figure, 11 is a first file group, 21 is a second file group, 131 is an update means, 41 is a group control means, and 51 is a file recovery means.

Claims (1)

[Scope of Claims] 1. A first file group and a second file group that is a copy of the first file are provided in order to prevent failures of the first file group, and each file is provided with a message indicating that the file is being updated. and a level storage means that indicates the update level, and when recovering from a failure due to a cause unrelated to the file group of the computer, it is possible to detect whether one of the corresponding files in the re-file group is being updated at the time the failure occurs. If
Restore the file that was being updated using the other file, and if both corresponding files in both file groups are not being updated at the time of failure, copy the newer update level file to the older update level file. In the duplex file system of a computer system, when at least two files in a group of files are updated in a group, a display indicating that the file is being updated in the group is now displayed for each individual file. A duplication file system characterized in that a group control means is provided to set/reset a predetermined storage means, and when a failure occurs, a file that was being updated in a group is restored with a file that was not being updated in a group. 2. As the predetermined storage means corresponding to the individual files, a group update storage means is provided corresponding to each file of the first file group and the second file group to indicate that group processing is in progress, and the group control means 2. The duplex file system according to claim 1, wherein the group processing display is seated/reset in the group update storage means. 3. An update storage means having each of the above files is used as a predetermined storage means corresponding to the individual files, and the group control means sets/resets a group processing in progress display to the update storage means. A duplex file system as claimed in claim 1.