Cache memory managing method for computer system

• US 20070245088A1
• Filed: 06/05/2007
• Published: 10/18/2007
• Est. Priority Date: 03/31/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Mogi, Kazuhiko, Nishikawa, Norifumi
• Granted Patent: US 7,500,058 B2
• Time in Patent Office: Days
• US Class Current: 711/120
• CPC Class Codes: G06F 12/0811 with multilevel cache hierarchies
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 12/0871 Allocation or management of cache space
• CPC Class Codes: G06F 12/0873 Mapping of cache memory to specific storage devices or parts thereof
• CPC Class Codes: G06F 12/0897 with two or more cache hierarchy levels with multilevel cache hierarchies G06F12/0811
• CPC Class Codes: G06F 16/2282 Tablespace storage structures; Management thereof
• CPC Class Codes: G06F 16/24552 Database cache management
• CPC Class Codes: G06F 2212/465 Structured object, e.g. database record
• CPC Class Codes: Y10S 707/99931 Database or file accessing

Abstract

A computer system acquires mapping information of data storage regions in respective layers from a layer of DBMSs to a layer of storage subsystems, grasps correspondence between DB data and storage positions of each storage subsystem on the basis of the mapping information, decides a cache partitioning in each storage subsystem on the basis of the correspondence and sets the cache partitioning for each storage subsystem. When cache allocation in the DBMS or the storage subsystem needs to be changed, information for estimating the cache effect due to the change in cache allocation acquired by the DBMS is used for estimating the cache effect in the storage subsystem.

Claims

1. A computer system comprising:

computers on which a plurality of programs operate respectively;

storage subsystems connected to said computers and provided for storing data sent from said computers, each storage subsystem having a plurality of logical units; and

a management device connected to said computers and said storage subsystems,

wherein each of said computers includes a first cache memory that is partitioned into one or more partitioned cache regions on the basis of the kinds of data managed by programs operating on said each of said computers,

wherein each of said storage subsystems includes a second cache memory,

wherein said management device acquires information concerning said programs from one of said computers, acquires information concerning mapping of data between said one of said computers and a corresponding one of said storage subsystems, decides a partitioning of said second cache memory in said corresponding storage subsystem by using said information concerning said programs and said information concerning mapping of said data, and instructs said corresponding storage subsystem to set partitioning of said second cache memory in accordance with said decided partitioning,

wherein said partitioned cache regions of said first cache memory have one-to-one correspondence with partitioned regions of said second cache memory,

wherein each one-to-one corresponding partitioned cache region of said first cache memory and partitioned region of said second cache memory correspond to the same one or more logical units.

3. A computer system according to claim 1, wherein said management device

classifies the storage region of each storage subsystem into groups by the kinds of data managed by said programs on the basis of said information concerning mapping, and

decides a partitioning of said storage region of said second cache memory in accordance with said storage region groups.

5. A computer system according to claim 3, wherein said management device

stores correspondence so that first storage regions allocated to said first cache memory partitioned are associated with second storage regions of said second cache memory allocated to said groups, and

instructs said computers and said storage subsystems to provide a predetermined mode common to said first and second storage regions.

7. A computer system according to claim 5, wherein said predetermined mode is a mode in which when each computer deletes data from said first storage regions, said computer instructs a corresponding storage subsystem to hold the deleted data in said second storage regions and in which when each computer reads data from said second storage regions, said storage subsystem deletes the read data from said second storage regions.

8. A computer system according to claim 7, wherein said management device receives information concerning the quantity of change in storage capacity of said first storage regions or said second storage regions, receives information concerning the cache hit ratios of said first storage regions and said second storage regions from said computers and predicts the cache hit ratios of said first storage regions and said second storage regions on the basis of said information concerning the quantity of change and said information concerning the cache hit ratios when the capacity of said first storage regions or said second storage regions is actually changed on the basis of the quantity of change.

9. A computer system according to claim 8, wherein said management device sends an instruction to said computers or said storage subsystems to change the capacity of said first storage regions or said second storage regions on the basis of the received quantity of change.

10. A computer system according to claim 9, wherein said management device uses said first storage regions and said second storage regions as one virtual storage region and calculates cache hit ratios in said virtual storage region to thereby predict the cache hit ratios of said first storage regions and said second storage regions.

11. A computer system according to claim 10, wherein each of said computers acquires cache hit number distribution information which is statistical information concerning positions in cache management information at the time of access to data in said first storage regions,

wherein said information concerning cache hit ratios is said cache hit number distribution information, and

wherein said management device calculates estimated values of the number of cache hits in said second storage regions of said storage subsystems by using said cache hit number distribution information.

12. A computer system according to claim 10, wherein each of said storage subsystems collects second cache hit number distribution information in said second storage regions, and

wherein said management device acquires said second cache hit number distribution information from said storage subsystem and predicts the cache hit ratios of said first and second storage regions.

2. A computer system comprising:

computers on which a plurality of programs operate respectively;

storage subsystems connected to said computers and provided for storing data sent from said computers, each storage subsystem having a plurality of logical units; and

a management device connected to said computers and said storage subsystems,

wherein each of said computers includes a first cache memory that is partitioned into one or more partitioned cache regions on the basis of management units for storage region management used by said programs operating on said each of said computers,

wherein each of said storage subsystems includes a second cache memory,

wherein said management device acquires information concerning said programs from one of said computers, acquires information concerning mapping of data between said one of said computers and a corresponding one of said storage subsystems, decides a partitioning of said second cache memory in said corresponding storage subsystem by using said information concerning said programs and said information concerning mapping of said data, and instructs said corresponding storage subsystem to set partitioning of said second cache memory in accordance with said decided partitioning,

wherein said partitioned cache regions of said first cache memory have one-to-one correspondence with partitioned regions of said second cache memory,

wherein each one-to-one corresponding partitioned cache region of said first cache memory and partitioned region of said second cache memory correspond to the same one or more logical units.

4. A computer system according to claim 2, wherein said management device

classifies the storage region of each storage subsystem into groups by storage regions for storing said management units for storage region management on the basis of said information concerning mapping, and

decides a partitioning of said storage region of said second cache memory-in accordance with said storage region groups.

6. A computer system according to claim 4, wherein said management device

stores correspondence so that first storage regions allocated to said first cache memory partitioned are associated with second storage regions of said second cache memory allocated to said groups, and

instructs said computers and said storage subsystems to provide a predetermined mode common to said first and second storage regions.

13. A cache memory management program embodied on a computer-readable medium for a computer system including computers, each computer having a first cache memory, storage subsystems each provided for storing data of application programs executing on said computers and having a second cache memory, and a management device connected to said computers and said storage subsystems, comprising the steps of:

acquiring cache hit number distribution information concerning said first and second cache memories, cache hit number distribution information for said first cache being collected by said computers and cache hit number distribution information for said second cache being collected by said storage subsystems, said first cache of each computer being partitioned on the basis of the kinds of data managed by application programs operating on said each computer;

acquiring information concerning a cache partitioning from said computers and said storage subsystems;

acquiring information concerning mapping of data from said computers and said storage subsystems;

acquiring an expected quantity of change in cache allocation for said first or second cache memory; and

calculating an estimated value of the number of cache hits in said second cache memory in each storage subsystem at the time of change in cache allocation in said computer system by using said information concerning said partitioning, said information concerning mapping and said expected quantity and outputting said estimated value.

14. A cache memory management program according to claim 13, wherein said cache memory management program is executed by any of said computers.

15. A cache memory management program embodied on a computer-readable medium for a computer system including computers, each computer having a first cache memory, storage subsystems each provided for storing data of application programs executing on said computers and having a second cache memory, and a management device connected to said computers and said storage subsystems, comprising the steps of:

acquiring cache hit number distribution information concerning said first and second cache memories, cache hit number distribution information for said first cache being collected by said computers and cache hit number distribution information for said second cache being collected by said storage subsystems, said first cache of each computer being partitioned on the basis of management units for storage region management used by said application programs operating on said each computer;

acquiring information concerning a cache partitioning from said computers and said storage subsystems;

acquiring information concerning mapping of data from said computers and said storage subsystems;

acquiring an expected quantity of change in cache allocation for said first or second cache memory; and

calculating an estimated value of the number of cache hits in said second cache memory in each storage subsystem at the time of change in cache allocation in said computer system by using said information concerning said partitioning, said information concerning mapping and said expected quantity and outputting said estimated value.

16. A cache memory management program according to claim 15, wherein said cache memory management program is executed by any of said computers.