Method, system, and program for improved throughput in remote mirroring systems

• US 20050228954A1
• Filed: 06/03/2005
• Published: 10/13/2005
• Est. Priority Date: 03/11/2003
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Zlotnick, Aviad, Micka, William Frank, Jarvis, Thomas Charles, Hyde, Joseph Smith II, Fienblit, Shachar, Spear, Gail Andrea, Factor, Michael E., Gluck, Olympia, Tross, Martin Jacob
• Granted Patent: US 7,581,063 B2
• Time in Patent Office: Days
• US Class Current: 711/134
• CPC Class Codes: G06F 11/1451 by selection of backup contents
• CPC Class Codes: G06F 11/1658 Data re-synchronization of a redundant component, or initial sync of replacement, additional or spare unit
• CPC Class Codes: G06F 11/1666 where the redundant component is memory or memory area
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 11/2066 Optimisation of the communication load
• CPC Class Codes: G06F 11/2074 Asynchronous techniques

Abstract

Disclosed is a method, system, and program for managing metadata in cache. A first policy is used to determine when to remove data from a primary cache, and a second policy is used to determine when to remove data from a metadata cache.

Claims

1. A method for managing metadata in cache, comprising:

using a first policy to determine when to remove data from primary cache; and

using a second policy to determine when to remove data from metadata cache.

2. The method of claim 1, wherein use of different policies for the metadata cache and the primary cache reduces an amount of data transferred from the primary cache to remote storage.

3. The method of claim 1, wherein the data removed from the primary cache comprises one or more blocks of data.

4. The method of claim 1, wherein the first policy comprises a least recently used policy.

5. The method of claim 1, wherein the data removed from the metadata cache comprises a metadata cache modified sub-blocks structure.

6. The method of claim 1, wherein the second policy comprises a least recently used policy.

7. The method of claim 1, wherein the second policy comprises a most recently used policy.

8. The method of claim 1, wherein the second policy comprises a penalty based policy.

9. The method of claim 8, wherein the second policy comprises removing a metadata cache modified sub-blocks structure with a largest number of indicators indicating that sub-blocks have been modified since a block of data was last transferred to remote storage.

10. A system for managing metadata in cache, comprising:

means for using a first policy to determine when to remove data from primary cache; and

means for using a second policy to determine when to remove data from metadata cache.

11. An article of manufacture for managing metadata in cache, wherein the article of manufacture causes operations, the operations comprising:

using a first policy to determine when to remove data from primary cache; and

using a second policy to determine when to remove data from metadata cache.

12. The article of manufacture of claim 11, wherein use of different policies for the metadata cache and the primary cache reduces an amount of data transferred from the primary cache to remote storage.

13. The article of manufacture of claim 11, wherein the data removed from the primary cache comprises one or more blocks of data.

14. The article of manufacture of claim 11, wherein the first policy comprises a least recently used policy.

15. The article of manufacture of claim 11, wherein the data removed from the metadata cache comprises a metadata cache modified sub-blocks structure.

16. The article of manufacture of claim 11, wherein the second policy comprises a least recently used policy.

17. The article of manufacture of claim 11, wherein the second policy comprises a most recently used policy.

18. The article of manufacture of claim 11, wherein the second policy comprises a penalty based policy.

19. The article of manufacture of claim 18, wherein the second policy comprises removing a metadata cache modified sub-blocks structure with a largest number of indicators indicating that sub-blocks have been modified since a block of data was last transferred to remote storage.