JPH0789332B2 - File migration / recall method - Google Patents

Description

The present invention relates to a file migration / recall method for improving the efficiency of use of an external storage device that stores data managed in an electronic computer system.

[Conventional technology]

A system that efficiently stores a large amount of data and guarantees access performance to the data in a large-scale computer system is called a storage management system.
This storage management system hierarchically manages various external storage devices connected to the computer system according to performance and capacity, and the system automatically performs the optimum arrangement of data desired by the user. One of the functions is the migration / recall function.

The migration / recall function guarantees data access performance from users by placing frequently accessed data in a high-speed external storage device and placing infrequently accessed data in a low-speed external storage device. In addition, it is intended to improve the usage efficiency for a high-cost and high-speed external storage device and a low-cost and low-speed external storage device. For example, the method shown in Japanese Patent Application No. 62-162047 is considered. There is. In this method, when access to a file is completed, file-based migration is executed, the entire file is transferred to a low-speed device, and the original file is deleted. Next, when the access to the file is resumed, the subfile which is the target of the access to the pool file that has been secured in advance is recalled. The pool file is shared by a plurality of transfer destination files. When the access on the pool file is completed, it is migrated to the transfer destination file in subfile units.

[Problems to be Solved by the Invention]

Such a conventional migration / recall method has the following drawbacks because the migration file is created corresponding to each original file.

That is, considering that the migration file needs to have the capacity to store all the contents of each original file, and that the recalled and updated subfiles are returned to the migration file again, It is necessary to reserve the capacity in advance so that it is larger than each original file. Therefore, the use efficiency of the space of the storage device may decrease. Also, the recall destination file is a space that is commonly used by multiple migration files (hence the original files). Therefore, if the recall destination file has a small capacity or a large recall volume, the recall destination space may be insufficient. Will be invited. For this reason, forced migration frequently occurs to secure the space, which may lead to deterioration in access performance.

[Means for solving problems]

The method of the present invention includes a pool file unit that stores each of a plurality of subfiles that are logically closed and that are individually accessible at the time of migration, and a migration destination of a subfile that stores information indicating the migration destination of the subfile. An information storage unit, a migration unit that transfers the subfile from the original file that is the migration source to the pool file based on the migration destination information from the migration destination information storage unit, and the original information that indicates the migration source by the migration unit. The original information storage means for storing the original information from the pool file means when resuming access to the subfile based on the original information from the original information storage means. And a recall means for recalling the sub-file to the file.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

Referring to FIG. 1, an embodiment of the present invention has an original file 1 having a plurality of subfiles and directly accessed by a user, a subfile migration destination information storage means 2, a subfile migration means 3, a subfile. Recall means 4, pool file 5, and subfile original file information storage means 6
Is equipped with. The subfile migration destination information storage unit 2 is information created when the subfile stored in the original file 1 is migrated to the pool file 5, and for each subfile, the migrated pool file is described. Stores the information of. The sub-file migration means 3 migrates the sub-files in the original file 1 that are the target of migration to the pool file 5. The subfile recall means 4 is called when a subfile in the original file 1 is requested to be accessed and migration to the pool file 5 is determined by the migration destination information of the subfile.
Recall from the pool file 5 to the original file 1 based on the location of the pool file and the migration destination information. Pool file 5 is original file 1
The sub-file in is a file to be migrated, and is commonly used by a plurality of original files 1. The subfile original file information storage unit 6 stores information about from which original file 1 the migrated subfile existing in the pool file 5 is migrated.

In the embodiment of FIG. 1, only one original file 1 for each pool file 5 is shown, but in the case of a configuration in which a plurality of original files 1 share one pool file 5 and use it, 1 The space between each original file 1 and the pool file 5 has the structure shown in FIG.

In this case, the subfile original file information storage means 6 stores the information of the original file 1 from which a plurality of migrated subfiles existing in the pool file 5 are set, and this information is stored. Use, pool file 5
It is possible to determine which of the plurality of original files 1 is to be recalled when the sub file is recalled.

Referring to FIG. 2, for the subfile in the original file 1, there is a directory for managing the subfile, and the address in the file in which the subfile is stored is stored. Next, when the access to the sub-file is completed and the sub-file is migrated to the pool file 5, the sub-file directory in the original file 1 stores information about the migrated destination pool file 5. For example, the pool file name and the subfile name in the pool file name (pool file subfile name). This subfile name must be generated so that it is unique within the pool file.

Referring to FIG. 3, the sub file is the pool file 5
When the file is migrated to, the subfile data is stored and at the same time, a directory for managing the subfile is created. In the directory, information about the original file 1 in which the sub files were stored (original file name and sub file name) and pool file 5
The address of the subfile data stored in is stored.

Subfile migration is performed by the following procedure.

Referring to FIG. 1, first, after the subfiles in the original file 1 have been accessed, if migration is decided, the migration destination pool file 5 is selected. In many cases, this determination is based on the fact that the time during which access is not normally made is set to a fixed value, and access is not performed above that value. Further, the selection of the pool file 5 is often based on information managed in advance in the form of a pool file name of a migration destination by a file catalog or the like that manages the original file 1. This way, the subfiles that should be migrated,
When the pool file 5 of the migration destination is determined, the subfile migration means 3 is activated. The subfile migration means 3 first reads the subfile data according to the subfile management information in the original file 1. Then, a new subfile is created in the pool file 5 to transfer the data.
The subfile management information in the pool file 5 stores information about the original file (original file name and subfile name). Finally, the subfile in the original file 1 is deleted.

Next, the recall of the sub file is executed by the following procedure.

The access request to the sub file is made to the original file 1. The file management information in the original 1 stores information about the pool file 5 at the migration destination. Therefore, when it is determined that the data of the sub file does not exist in the original 1, the sub file recall means 4 is activated. The sub-file recall means 4 accesses the pool file 5 based on the pool file information in the directory, and searches the directory of the pool file 5 using the pool file name as a key. Since the address to the data of the target subfile is stored in the directory, the data is read accordingly. Then, a subfile is created in the original file with the original subfile name, and the subfile data is transferred from the pool file. When the transfer is complete, the subfiles in the pool file are deleted.

The original file information of the subfile stored in the pool file is used in the following cases.

That is, when pool files are provided in multiple layers,
Subfile is a slower and larger pool file 5
Be transferred to. At this time, it is used as information when rewriting the migration destination information of the subfile stored in the original file 1 to the information of the new pool file.

Further, since the usage status of the pool file 9 is known, the original file 1 can be specified by the information.

Further, in the recall process of the subfile specifying the pool file 5, the original file of the recall destination is specified.

〔The invention's effect〕

As described above in detail, according to the migration / recall method of the present invention, migration is performed in units of individually accessible subfiles, and only necessary subfiles are recalled to the user's file for use. The file size that should be secured by a person can be reduced, and since the file to which the subfile is migrated is shared by multiple files, there is an effect that the utilization efficiency of the file capacity at the migration destination is improved. .

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing an example of contents of files and stored information in FIG. 1 to 3, 1 ... Original file, 2 ... Subfile migration destination information storage means, 3 ... Subfile migration means, 4 ... Subfile recall means, 5 ... Pool file, 6 ...
... Original file information storage means of sub-file.

Claims (1)

[Claims] 1. A pool file means for storing each of a plurality of logically closed and individually accessible subfiles at the time of migration, and a migration destination information storage means for storing information indicating a migration destination of the subfile. , A migration means for transferring the subfile from the original file as the migration source to the pool file based on the migration destination information from the migration destination information storage means, and the original information for storing the original information indicating the migration source by the migration means Storage means, and based on the original information from the original information storage means, when the access to the subfile is resumed, the pool file means stores the original file in the original file. And a recall means for recalling a file.