FAST ACCESSIBLE COMPRESSED THIN PROVISIONING VOLUME

• US 20090144496A1
• Filed: 11/30/2007
• Published: 06/04/2009
• Est. Priority Date: 11/30/2007
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: KAWAGUCHI, Tomohiro
• Granted Patent: US 8,131,927 B2
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A computerized data storage system includes at least one storage device including a nonvolatile writable medium; a cache memory operatively coupled to the storage port and including a data storing area and a data management controller and a storage port. The storage port is operable to connect to a host computer, receive and send I/O information required by the host computer. The storage port is also operable to receive a request to read data, and, in response to the request to read data, the storage port is operable to send the data stored in the data storing area of the cache memory. The storage port is further operable to receive a request to write data, and, in response to the request to write data, the storage port is operable to send the write data to the data storing area of the cache memory. The storage system further includes a thin provisioning controller operable to provide a virtual volume having a virtual volume page, a capacity pool having a capacity pool page and manage a mapping between the virtual volume page and the capacity pool page. The storage system further includes a data compression controller operable to perform a compression operation, and a data decompression controller operable to perform a decompression operation.

Claims

1. A computerized data storage system comprising:

a. at least one storage device comprising a nonvolatile writable medium;

b. a cache memory operatively coupled to the storage port and comprising a data storing area and a data management controller;

c. a storage port, the storage port operable to connect to a host computer, receive and send I/O information required by the host computer, wherein the storage port is operable to receive a request to read data, and, in response to the request to read data, the storage port is operable to send the data stored in the data storing area of the cache memory and wherein the storage port is operable to receive a request to write data, and, in response to the request to write data, the storage port is operable to send the write data to the data storing area of the cache memory;

d. a thin provisioning controller, the thin provisioning controller operable to provide a virtual volume comprising a virtual volume page, a capacity pool comprising a capacity pool page and manage a mapping between the virtual volume page and the capacity pool page;

e. a data compression controller operable to perform a compression operation on the virtual volume page, and

f. a data decompression controller operable to perform a decompression operation on the virtual volume page.

2. The computerized data storage system of claim 1, wherein the data storing area has faster access parameters than the at least one storage device.

3. The computerized data storage system of claim 1, wherein the at least one storage device comprises a plurality of storage units arranged into a RAID or a JBOD composition.

4. The computerized data storage system of claim 1, wherein the data compression controller is further operable to:

i. compare an uncompressed data size and a compressed data size; and

ii. if the compressed data size is equal or larger than the uncompressed data size, skip the compression operation on the virtual volume page.

5. The computerized data storage system of claim 1, wherein the data management controller comprises a data caching controller operable to perform a data caching operation, a data staging controller operable to perform a data staging operation and a data destaging controller operable to perform a data destaging operation.

6. The computerized data storage system of claim 5, wherein the data caching controller manages the data storing area to speed up I/Os operations of the host computer by using a cache control algorithm.

7. The computerized data storage system of claim 5, wherein the data staging controller is operable to transfer data from the at least one storage device to the data storing area if the data has not been cached in the at least one storage device when the storage port attempts to send the data to the host computer.

8. The computerized data storage system of claim 5, wherein the data destaging controller is operable to transfer dirty data from the data storing area to the at least one storage device.

9. The computerized data storage system of claim 8, wherein the at least one storage device comprises a plurality of storage units arranged into a RAID5 or RAID6 configuration and wherein the destaging controller is further operable to recalculate parity data and modify the parity data before the destaging operation.

10. The computerized data storage system of claim 1, wherein the virtual volume has no or limited capacity when it is established and is allocated capacity on demand.

11. The computerized data storage system of claim 1, wherein the capacity pool comprises a group of the storage devices, and provides at least some capacity area of the group of the storage devices to the virtual volume for storing virtual volume data.

12. The computerized data storage system of claim 1, wherein the virtual volume page comprises at least a portion of the virtual volume and represents a unit of virtual volume capacity allocation management.

13. The computerized data storage system of claim 1, wherein a capacity pool page comprises at least a portion of the capacity pool and represents a unit of virtual volume capacity provisioning management.

14. The computerized data storage system of claim 1, wherein the data compression controller is operable to interrupt data destaging operation by the data destaging controller.

15. The computerized data storage system of claim 14, wherein after the interruption, the data compression controller is operable to compress data and provide the compressed data size to the thin provisioning controller.

16. The computerized data storage system of claim 15, wherein following receipt of the compressed data size, the capacity controller is operable to reallocate a new capacity pool page and free used capacity pool page.

17. The computerized data storage system of claim 15, wherein after the reallocating, the compression controller is operable to return operation to the destaging controller and the destaging controller is operable to continue the destaging operation.

18. The computerized data storage system of claim 1, wherein the data compression controller is operable to compress data to generate a compressed page comprising compression management information, the compression management information being selected from a group consisting of compression dictionary information and check sum information.

19. The computerized data storage system of claim 1, wherein the data decompression controller is operable to interrupt the data staging operation by said data staging controller.

20. The computerized data storage system of claim 19, wherein after the interruption, the data decompression controller is operable to decompress the data and return the operation to the staging controller and wherein the staging controller is operable to continue the staging operation.

21. A method to be performed by a computerized data storage system, the method comprising:

a. providing a virtual volume, the virtual volume comprising a virtual volume page;

b. providing a capacity pool comprising a capacity pool page;

c. managing a mapping between the virtual volume page and the capacity pool page;

d. providing a data caching area storing data;

e. receiving a request to read data from a host computer, and, in response to the request to read data, sending to the host computer the data stored in the data caching area;

f. receiving a request to write data from the host computer, and, in response to the request to write data, writing the write data provided by the host computer to the data caching area;

g. performing a compression operation on the virtual volume page, and

h. performing a decompression operation on the virtual volume page.

22. The method of claim 21, further comprising:

i. comparing an uncompressed data size and a compressed data size; and

ii. if the compressed data size is equal or larger than the uncompressed data size, skipping the compression operation on the virtual volume page.

23. The method of claim 21, further comprising:

i. performing a data caching operation;

ii. performing a data staging operation; and

iii. performing a data destaging operation.

24. A computer-readable medium embodying a set of instructions, the set of instructions, when executed by a storage system comprising one or more processors, causes the storage system to:

a. provide a virtual volume, the virtual volume comprising a virtual volume page;

b. provide a capacity pool comprising a capacity pool page;

c. manage a mapping between the virtual volume page and the capacity pool page;

d. provide a data caching area storing data;

e. receive a request to read data from a host computer, and, in response to the request to read data, send to the host computer the data stored in the data caching area;

f. receive a request to write data from the host computer, and, in response to the request to write data, write the write data provided by the host computer to the data caching area;

g. perform a compression operation on the virtual volume page, and

h. perform a decompression operation on the virtual volume page.

25. The computer-readable medium of claim 24, wherein the set of instructions further causes the storage system to:

i. compare an uncompressed data size and a compressed data size; and

ii. if the compressed data size is equal or larger than the uncompressed data size, skip the compression operation on the virtual volume page.

26. The computer-readable medium of claim 24, wherein the set of instructions further causes the storage system to:

i. perform a data caching operation;

ii. perform a data staging operation; and

iii. perform a data destaging operation.