Method, system, and article of manufacture for optimizing storage utilization

• US 20030236942A1
• Filed: 06/20/2002
• Published: 12/25/2003
• Est. Priority Date: 06/20/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Kishi, Gregory Tad, Onton, Aare
• Granted Patent: US 6,868,478 B2
• Time in Patent Office: Days
• US Class Current: 711/113
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0686 Libraries, e.g. tape libraries, jukebox

Abstract

Provided are a method, system, and an article of manufacture for optimizing storage utilization. Logical volumes are stored in a cache, wherein the cache is coupled to a plurality of physical devices. An optimum number of physical devices selected from the plurality of physical devices is determined. The logical volumes are transferred from the cache to the optimum number of physical devices.

Claims

1. A method for optimizing storage utilization, the method comprising:

storing logical volumes in a cache, wherein the cache is coupled to a plurality of physical devices;

determining an optimum number of physical devices selected from the plurality of physical devices; and

transferring data in the logical volumes from the cache to the optimum number of physical devices.

2. The method of claim 1, wherein the plurality of physical devices are addressed by a host via a plurality of logical devices, and wherein the determining further comprises:

comparing a number of logical devices in use with a predetermined number of logical devices; and

based on the comparison determining the optimum number of physical devices.

3. The method of claim 1, wherein the determining further comprises:

comparing a data transfer rate at the cache with a predetermined maximum data transfer rate at the cache; and

based on the comparison determining the optimum number of physical devices.

4. The method of claim 1, wherein the cache and the physical devices are controlled by a virtual tape server in communication with a plurality of hosts, and wherein the determining further comprises:

comparing a data transfer rate between the hosts and the virtual tape server with a predetermined maximum data transfer rate; and

based on the comparison determining the optimum number of physical devices.

5. The method of claim 1, wherein the determining further comprises:

comparing a CPU utilization rate with a predetermined CPU utilization rate; and

based on the comparison, determining the optimum number of physical devices.

6. The method of claim 1, wherein the determining further comprises:

calculating an extent of data transfer between the cache and the physical devices; and

based on the calculation determining the optimum number of physical devices.

7. The method of claim 1, wherein the determining further comprises:

comparing the average size of the logical volumes that are queued for premigration to the physical devices; and

based on the comparison, determining the optimum number of physical devices.

8. The method of claim 1, wherein:

the cache comprises a DASD file buffer;

a plurality of physical volumes are mountable on the physical devices; and

the cache and the physical devices are coupled to a virtual tape server that is coupled to a host.

9. The method of claim 8, wherein a request from the host for one logical volume is satisfied by the virtual tape server by:

determining if the one logical volume is available in the cache;

if the one logical volume is available in the cache, satisfying the request from the cache;

if the one logical volume is unavailable in the cache, determining if the corresponding physical volume is mounted on the physical devices;

if the corresponding physical volume is mounted on the physical devices, then transferring the one logical volume to the cache, and satisfying the request; and

if the corresponding physical volume is not mounted on the physical devices then mounting the corresponding physical volume to the physical devices, transferring the one logical volume to the cache, and satisfying the request.

10. The method of claim 1, wherein the cache is coupled to the physical devices by a virtual tape server.

11. The method of claim 1, wherein transferring further comprises premigrating data from the logical volumes to the physical devices.

12. A system for optimizing storage utilization, the system comprising:

a cache;

a plurality of physical devices coupled to the cache;

means for storing logical volumes in the cache;

means for determining an optimum number of physical devices selected from the plurality of physical devices; and

means for transferring data in the logical volumes from the cache to the optimum number of physical devices.

13. The system of claim 12, wherein the plurality of physical devices are addressed by a host via a plurality of logical devices, and wherein the means for determining further performs:

comparing a number of logical devices in use with a predetermined number of logical devices; and

based on the comparison determining the optimum number of physical devices.

14. The system of claim 12, wherein the means for determining further performs:

comparing a data transfer rate at the cache with a predetermined maximum data transfer rate at the cache; and

based on the comparison determining the optimum number of physical devices.

15. The system of claim 12, further comprising a virtual tape server, wherein the cache and the physical devices are controlled by the virtual tape server in communication with a plurality of hosts, and wherein the means for determining further performs:

comparing a data transfer rate between the hosts and the virtual tape server with a predetermined maximum data transfer rate; and

based on the comparison determining the optimum number of physical devices.

16. The system of claim 12, wherein the means for determining further performs:

comparing a CPU utilization rate with a predetermined CPU utilization rate; and

based on the comparison, determining the optimum number of physical devices.

17. The system of claim 12, wherein the means for determining further performs:

calculating an extent of data transfer between the cache and the physical devices; and

based on the calculation determining the optimum number of physical devices.

18. The system of claim 12, wherein the means for determining further performs:

comparing the average size of the logical volumes that are queued for premigration to the physical devices; and

based on the comparison, determining the optimum number of physical devices.

19. The system of claim 12, further comprising a plurality of physical volumes, a DASD file buffer and a virtual tape server, wherein:

the cache comprises the DASD file buffer;

the physical devices are coupled to the plurality of physical volumes mountable on the physical devices; and

the cache and the physical devices are coupled to the virtual tape server that is coupled to a host.

20. The system of claim 19, wherein a request from the host for one logical volume is satisfied by the virtual tape server by:

determining if the one logical volume is available in the cache;

if the one logical volume is available in the cache, satisfying the request from the cache;

if the one logical volume is unavailable in the cache, determining if the corresponding physical volume is mounted on the physical devices;

if the corresponding physical volume is mounted on the physical devices, then transferring the one logical volume to the cache, and satisfying the request; and

if the corresponding physical volume is not mounted on the physical devices then mounting the corresponding physical volume to the physical devices, transferring the one logical volume to the cache, and satisfying the request.

21. The system of claim 12, wherein the cache is coupled to the physical devices by a virtual tape server.

22. The system of claim 12, wherein the means for transferring further comprises premigrating data from the logical volumes to the physical devices.

23. An article of manufacture including code for optimizing storage utilization, wherein the article of manufacture is capable of causing operations, the operations comprising:

storing logical volumes in a cache, wherein the cache is coupled to a plurality of physical devices;

determining an optimum number of physical devices selected from the plurality of physical devices; and

transferring data in the logical volumes from the cache to the optimum number of physical devices.

24. The article of manufacture of claim 23, wherein the plurality of physical devices are addressed by a host via a plurality of logical devices, and wherein the determining further comprises:

comparing a number of logical devices in use with a predetermined number of logical devices; and

based on the comparison determining the optimum number of physical devices.

25. The article of manufacture of claim 23, wherein the determining further comprises:

comparing a data transfer rate at the cache with a predetermined maximum data transfer rate at the cache; and

based on the comparison determining the optimum number of physical devices.

26. The article of manufacture of claim 23, wherein the cache and the physical devices are controlled by a virtual tape server in communication with a plurality of hosts, and wherein the determining further comprises:

comparing a data transfer rate between the hosts and the virtual tape server with a predetermined maximum data transfer rate; and

based on the comparison determining the optimum number of physical devices.

27. The article of manufacture of claim 23, wherein the determining further comprises:

comparing a CPU utilization rate with a predetermined CPU utilization rate; and

based on the comparison, determining the optimum number of physical devices.

28. The article of manufacture of claim 23, wherein the determining further comprises:

calculating an extent of data transfer between the cache and the physical devices; and

based on the calculation determining the optimum number of physical devices.

29. The article of manufacture of claim 23, wherein the determining further comprises:

comparing the average size of the logical volumes that are queued for premigration to the physical devices; and

based on the comparison, determining the optimum number of physical devices.

30. The article of manufacture of claim 23, wherein:

the cache comprises a DASD file buffer;

a plurality of physical volumes are mountable on the physical devices; and

the cache and the physical devices are coupled to a virtual tape server that is coupled to a host.

31. The article of manufacture of claim 30, wherein a request from the host for one logical volume is satisfied by the virtual tape server by:

determining if the one logical volume is available in the cache;

if the one logical volume is available in the cache, satisfying the request from the cache;

if the one logical volume is unavailable in the cache, determining if the corresponding physical volume is mounted on the physical devices;

if the corresponding physical volume is mounted on the physical devices, then transferring the one logical volume to the cache, and satisfying the request; and

if the corresponding physical volume is not mounted on the physical devices then mounting the corresponding physical volume to the physical devices, transferring the one logical volume to the cache, and satisfying the request.

32. The article of manufacture of claim 23, wherein the cache is coupled to the physical devices by a virtual tape server.

33. The article of manufacture of claim 23, wherein transferring further comprises premigrating data from the logical volumes to the physical devices.