JP2006039942A - File management device in hierarchical storage system, and its file management method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a file management device which can perform file access to a primary storage without performing data restoration from a secondary storage even if after moving file data to the secondary storage from the primary storage in a hierarchical storage system. <P>SOLUTION: When an input/output request to a migrated file is made, a file information management section 11 checks whether or not the file data remains on the primary storage 51 with reference to a file information table 2. If file data is remains on the primary storage, input/output are performed to the primary storage without performing recall from the secondary storage 52. Furthermore, deletion of data of an access target file is performed from an available area management table 4, a file status currently recorded on the file information table 2 is updated to a non-migration status, and restoration of file data on the primary storage is performed without accessing the secondary storage. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a file management method after moving (migrating) file data from a primary storage device to a secondary storage device having a low data access speed in a hierarchical storage system.

  Conventionally, when a file is migrated, the data area assigned to the file is generally released as a free area and cannot be accessed in the same manner as when the file is deleted. For this reason, a file that has been migrated must be accessed after the file data is restored by a recall.

  In a hierarchical storage system in which migration to a lower storage device is performed automatically depending on the free capacity of the file system, etc., when recalling a file to be used in a user job in advance prior to job execution, Depending on the migration policy, there is a possibility that migration will occur again by the time the job is executed, and there is a problem that a recall process that takes time again during file access operates.

  Even if you want to access a file immediately after migration, a time-consuming recall is required.

In addition, there is a processing method that shortens the output processing of a user program by inputting and outputting files via a large-capacity and high-speed extended storage device (see, for example, Patent Document 1).
JP-A-5-128004

  However, when a file is migrated, the area allocated to the file is released as a free area in the same way as the deleted file area, even before the contents are rewritten before it is allocated to another file. Could not access. Therefore, when the secondary storage device has a large difference in data access speed from the host storage device such as a sequential access medium such as a magnetic tape library device, data remains in the primary storage device. However, it took a long time to recall the file data.

  Therefore, the present invention provides a file data area that is released as a free area during migration even after file data is migrated (migrated) from a primary storage apparatus to a secondary storage apparatus having a low data access speed in a hierarchical storage system. As long as the file is not assigned to another file, it enables high-speed access and data recovery to the primary storage device without performing data recovery (recall) from the secondary storage device during file input / output, and file system access It is an object of the present invention to provide a file management apparatus and a file management method thereof in a hierarchical storage system that reduce costs.

  In order to solve the above problems, the present invention provides a file information table 2 for storing file information necessary for file access, and an available area management table for managing areas on the primary storage device released by file migration. 4 and a free area management table 3 for managing areas on the primary storage device released by deleting other files.

  When there is an input / output request to the migrated file, the file information management unit 11 refers to the file information table 2 to check whether the file data remains on the primary storage device. If the file data is on the primary storage device 51, input / output to / from the primary storage device 51 is performed without recalling from the secondary storage device 52. Further, the file information management unit 11 deletes the data of the access target file from the usable area management table 4 through the file system area management unit 12, and updates the file state recorded in the file information table 2 to the non-migration state. The file data is restored onto the primary storage device 51 without accessing the secondary storage device 52.

  When allocating an area to a file, the area managed by the free area management table 3 is used first, and the area managed by the usable area management table 4 is used only when there is no area in the free area management table 3 To do.

  The first effect of the present invention is that the input / output waiting time of a process for performing file input / output is reduced, and the file access speed as seen in the entire system is improved. This is because the number of times file data is recalled from a low-speed secondary storage device such as a magnetic tape during file input / output is reduced.

  The second effect is an improvement in the utilization efficiency of the file system area by accessing the area released at the time of migration.

  The third effect is a reduction in the load on the tape device and the tape medium, which are secondary storage devices, by reducing the number of migration / recalls.

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

  Referring to FIG. 1, the first embodiment of the present invention manages a file access means 1 under program control, a file information table 2 referenced / updated by the file access means 1, and an area on the primary storage device. The free area management table 3 and the usable area management table 4 and the storage device 5 are configured.

  The file access means 1 includes a file information management unit 11, a file system area management unit 12, a migration / recall unit 13, and a disk driver 14 and a tape driver 15 for accessing the storage device 5. The file information management unit 11 uses the file information table 2 to determine whether the file data exists on the primary storage device 51, and if necessary, performs a recall by the migration / recall unit 13. The file system area management unit 12 manages the area of the file system on the primary storage device 51 based on the free area management table 3 and the usable area management table 4, and allocates and releases the area. The migration / recall unit 13 moves file data between the primary storage device 51 and the secondary storage device 52.

  The file information table 2 is a table that stores file information necessary for accessing the file such as the file status and allocated area information, and corresponds to the file on a one-to-one basis.

  As the table for managing the area on the primary storage device, 2 of the available area management table 4 for managing the area released at the time of file migration and the free area management table 3 for managing the area released by other than migration such as file deletion. Hold the type.

  The storage device 5 includes a primary storage device 51 such as a magnetic disk device and a secondary storage device 52 such as a tape library device used as a migration destination of file data.

  FIG. 5 shows the relationship between the file information table 2, the free space management table 3 for managing the area on the primary storage device, and the usable area management table 4. The file management table 2 is assigned to a file, a file state 21 indicating whether the file is migrated, a file area state 22 indicating whether the file area released by migration is assigned to another file, and the file. An allocation area list 23 for recording an area and an area management table pointer 24 indicating area information registered as an available area at the time of migration are held.

  The free area management table 3 is a table that collectively manages unused areas on the primary storage device and areas released by releasing file areas other than migration, and indicates how much free area exists. A free area list 32 for recording the number of areas 31 and free areas is held.

  The usable area management table 4 is a table group for managing file area information released at the time of migration in a bi-directional list structure, and is registered at the time of migration with a management header 41 serving as a starting point and an ending point of the list. The area management table group for each file (element 42, element 43, element 44 in FIG. 5). The area management table (element 42, element 43, element 44) for each file includes pointers to previous and subsequent entries (element 421, element 431, element 441) and a file information table number (element 422) indicating the corresponding file information table. , Element 432, element 442) and an allocated area list (element 423, element 433, element 443) for recording the area allocated to the file. The allocation area list 23 of the file table 2 and the allocation area list (element 423, element 433, element 443) in the area management table for each file have a one-to-one correspondence.

  When a new entry is added to the usable area management table 4 by file migration, the entry is added after the management header 41, and the free area management table 3 runs out of space, and the entry is extracted from the usable area management table 4. In this case, the management header 41 is taken out. This is so that the oldest registered data is assigned to another file.

  The operation of the embodiment of the present invention will be described in detail below.

  First, the operation during file input / output will be described with reference to the flowchart of FIG. When there is a file input / output request, the file information management unit 11 refers to the file information table 2 to check the state of the file (step S1 in FIG. 2), and divides the processing depending on whether or not the file is migrated. (Step S2). If the file is not migrated, the file data is on the primary storage device, and input / output is performed from the primary storage device (step S7).

  If the file has been migrated, the processing is divided depending on whether the area of the file released as the usable area at the time of migration remains in the primary storage device 51 without being used for other files (step S3). If the file data is not in the primary storage device, the migration recall unit 13 recalls the file and waits for the end (step S4). If the file data remains on the primary storage device, the area information registered at the time of migration is deleted from the usable area management table 4 (step S5), and the file status recorded in the file information table 2 is not migrated. The state is changed (step S6). Since the file data is on the primary storage device, input / output is performed from the primary storage device 51 (step S7). In this way, file input / output and file data recovery can be performed without accessing the secondary storage device.

  Next, file area release processing will be described with reference to the flowchart of FIG. When releasing the area allocated to the file, the process is divided depending on whether or not the area is released by file migration (step S11 in FIG. 3). If the area is released by migration, the file area information is registered at the head of the usable area management table 4 (step S12).

  When the area is released by other than migration (file deletion or reduction processing is applicable), the file status and the file area status are checked in the file information table 2 (step S13), and depending on the file status and the area status, The process is separated (step S14 and step S16). If the file has not been migrated, the area allocated to the file is registered in the free area management table (step S15). If the file has been migrated and the file data remains in the primary storage device, the information on the area allocated to the file is registered in the usable area management table 4, so that file area information Is deleted from the usable area management table 4 and registered in the free area management table 3 (step S17).

  If the file has been migrated and the file data is not in the primary storage device, the area allocated to the file has been deleted from the usable area management table 4, and therefore used with the free area management table 3. The operation of the possible area management table 4 is not necessary.

  Next, an area allocation process for a file will be described with reference to the flowchart of FIG. When allocating an area to a file, the area is prioritized from the free area managed by the free area management table 3. Therefore, the process is first divided depending on whether or not there is a free area managed by the free area management table 3 (step S21 in FIG. 4). If there is a free area managed by the free area management table 3, the area is allocated to the file, and the free area management table 3 is updated (step S22).

  If there is no free area managed by the free area management table 3, it is checked whether there is an area managed by the usable area management table 4 (step S23). If there is an area managed by the usable area management table 4, the area information of the oldest one file managed by the usable area management table 4 is deleted, and the area is registered in the free area management table 3. (Step S24), the file area information of the file information table 2 is changed to an unusable state indicating that there is no data on the primary storage device (Step S25), and the process is repeated from the confirmation of the free area management table 3. . If there is no area managed by the usable area management table 4, an area shortage error occurs because there is no area that can be allocated to the file (step S26).

  Next, the configuration of the second embodiment of the present invention will be described in detail with reference to the drawings.

  Referring to FIG. 6, in the second embodiment of the present invention, the usable area management table 4 and the file information table 2 shown in FIG. A file area state bitmap 62 for managing the area and managing the area for each area allocation unit is held.

  The file area status bitmap 62 indicates whether each area recorded in the allocation area list 63 remains on the primary storage device for each allocation unit. As a result, when part of the file data remains in the primary storage device, the data can be input / output without recalling, which could not be realized in the first embodiment.

  Furthermore, an order to use the free area as the free area is provided in the area released by the migration, the area that is desired to remain in the primary storage device is the second usable area management table b, and the other areas are the first use. It is managed by the possible area management table a. If the free area management table 3 is empty when an area is allocated to a file, the area managed in the first usable area management table a is first used as a free area, and the first usable area management table a If there is no area, the area managed by the second usable area management table b is used. As a result, data that is desired to remain in the primary storage device can be retained on the primary storage device for a longer time.

  The following candidates are considered as areas to be managed by the second usable area management table b. The first candidate is the area where the last access was made and the areas before and after the area. This is because the area is expected to be accessed next. The second candidate is the area at the beginning and end of the file. This area is also considered as an easily accessible area. Other candidates include a file area recorded near the end of the magnetic tape. This is because time is required for the recall compared to the data at the head of the magnetic tape.

  According to the present invention, for file access in a hierarchical storage system having storage devices with different access speeds (a primary storage device with a high access speed and a secondary storage device with a slow access speed but a large capacity). Applicable.

It is a block diagram of the Example of this invention. It is a flowchart explaining the input / output operation of a file. It is a flowchart explaining a file area release process. It is a flowchart explaining the area | region allocation process to a file. FIG. 3 is a diagram illustrating a table configuration example according to the first embodiment. FIG. 10 is a diagram illustrating a table configuration example of Example 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 File access means 2 File information table 3 Free area management table 4 Usable area management table 5 Storage device 51 Primary storage device 52 Secondary storage device

Claims (7)

A primary storage device with high access speed;
Secondary storage device with slow access speed but large capacity,
File information necessary for file access including file status and allocated area information is stored, a file information table corresponding to the file one-to-one,
An available area management table for managing information of file areas on the primary storage device released at the time of migration;
A file access means for managing file access,
When there is a file input / output request, the file access means refers to the file information table to check the file status,
If the file has been migrated, check whether the area of the file released as the usable area at the time of migration remains in the primary storage device without being used for other files,
If the migrated file data is not on the primary storage device, the file is recalled from the secondary storage device, and if the migrated file data remains on the primary storage device, the Delete the area information registered during migration from the available area management table,
Change the file status recorded in the file information table to a non-migration status,
A file management apparatus in a hierarchical storage system, wherein files are input and output from the primary storage apparatus. A free area management table for managing an unused area on the primary storage device and an area released by releasing a file area other than migration;
The file access means is
In the case of area release by migration, register file area information at the top of the usable area management table,
In the case of area release other than migration, check the file status and area status in the file information table,
If the file is not migrated, register the area allocated to the file in the free space management table,
When the file is migrated and the file data remains in the primary storage device, the file area information is deleted from the usable area management table and registered in the free area management table. The file management apparatus in the hierarchical storage system according to claim 1. The file access means is
When allocating an area to a file, check whether there is a free area managed in the free area management table,
If there is a free area managed by the free area management table, the area is allocated to the file, the free area management table is updated,
If there is no free area managed by the free area management table, check whether there is an area managed by the usable area management table,
If there is an area managed by the usable area management table, the area information for the oldest one file managed by the usable area management table is deleted, and the area is registered in the free area management table. ,
Change the file area information of the file information table to an unusable state indicating that there is no data on the primary storage device, and repeat the process from the confirmation of the free area management table,
3. The file management apparatus in a hierarchical storage system according to claim 2, wherein when there is no area managed by the usable area management table, an error indicating an area shortage is generated. The areas to be released by migration are managed by the first and second usable area management tables, and each area recorded in the allocation area list of the file information table is stored in the primary storage device for each allocation unit. Provide a file area status bitmap indicating whether it remains,
An area that is freed by the migration is provided with an order of use as a free area, and the area that is desired to remain in the primary storage device is the second usable area management table, and other areas are the first usable area. Managed in the area management table,
When the free area management table is empty when an area is allocated to a file, the area managed in the first usable area management table is used as a free area, and the first usable area management table is used. 2. The file management apparatus according to claim 1, wherein when there is no area, an area managed by the second usable area management table is used. When there is a file input / output request, the file information necessary for file access including the file status and allocated area information is stored, and the file information table corresponding to the file is referenced one by one. Check the status of
If the file has been migrated, check whether the area of the file released as the usable area at the time of migration remains in the primary storage device with high access speed without being used for other files,
If the migrated file data is not on the primary storage device, the file is recalled from the secondary storage device with a slow access speed but a large capacity, and the migrated file data is stored on the primary storage device. In the case of remaining in the storage area, delete the area information registered at the time of migration from the usable area management table for managing the information of the file area on the primary storage device released at the time of migration,
Change the file status recorded in the file information table to a non-migration status,
A file management method in a hierarchical storage system, wherein file input / output is performed from the primary storage device. In the case of area release by migration, register file area information at the top of the usable area management table,
In the case of area release other than migration, check the file status and area status in the file information table,
If the file is not migrated, register the area allocated to the file in the free area management table that manages the unused area on the primary storage device and the area released by releasing the file area other than migration. ,
When the file is migrated and the file data remains in the primary storage device, the file area information is deleted from the usable area management table and registered in the free area management table. The file management method in the hierarchical storage system according to claim 5. When allocating an area to a file, check whether there is a free area managed in the free area management table,
If there is a free area managed by the free area management table, the area is allocated to the file, the free area management table is updated,
If there is no free area managed by the free area management table, check whether there is an area managed by the usable area management table,
If there is an area managed by the usable area management table, the area information for the oldest one file managed by the usable area management table is deleted, and the area is registered in the free area management table. ,
Change the file area information of the file information table to an unusable state indicating that there is no data on the primary storage device, and repeat the process from the confirmation of the free area management table,
7. The file management method in a hierarchical storage system according to claim 6, wherein when there is no area managed by the usable area management table, an error of insufficient area is generated.

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