Storage device and method for selective data compression

• US 8,918,579 B2
• Filed: 02/06/2012
• Issued: 12/23/2014
• Est. Priority Date: 02/06/2012
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Kettner, Doron
• Primary Examiner(s): Rutz, Jared
• Assistant Examiner(s): Namazi, Mehdi
• Application Number:
  US13/367,171
• Publication Number:
  US 20130205110A1
• Time in Patent Office: 1,051 Days
• Field of Search: 711/103, 711/E12.008, 711/162, 710/68
• US Class Current: 711/103
• CPC Class Codes: H03M 7/6064 Selection of Compressor

Abstract

A storage device and method for selective data compression are provided. In one embodiment, a storage device determines whether data stored in a storage area in the storage device'"'"'s memory is suitable for compression. If the data is suitable for compression, the storage device compresses the data. The storage device then uses free memory space resulting from compressing the data for an internal storage device operation. Other embodiments are disclosed, and each of the embodiments can be used alone or together in combination.

Claims

1. A method for selective user data compression, the method comprising:

performing the following in a storage device in communication with a host device, the storage device having a non-volatile memory;

determining whether user data stored in a storage area in the memory is suitable for compression;

if it is determined that the user data is suitable for compression, compressing the user data; and

using free memory space resulting from compressing the user data for an internal storage device operation, wherein a capacity reported to the host device as being available for storing additional user data remains unchanged after compressing the user data, and wherein the free memory space is not used for additional user data.

2. The method of claim 1, wherein determining whether user data is suitable for compression comprises determining whether the user data is backup data.

3. The method of claim 1, wherein determining whether user data is suitable for compression comprises determining a compression efficiency for the user data.

4. The method of claim 1, wherein determining whether user data is suitable for compression comprises determining an access frequency of the user data.

5. The method of claim 1 further comprising determining a compression algorithm to use to compress the user data.

6. The method of claim 1 further comprising determining a schedule for compressing the user data.

7. The method of claim 1 further comprising determining whether compressing the user data would violate a rule.

8. The method of claim 7, wherein the rule is violated if a logical partition is reformatted.

9. The method of claim 7, wherein the rule is violated if a change is made to user data that is frequently accessed or modified.

10. The method of claim 1 further comprising monitoring I/O transactions from the host device to determine if a rule is violated by utilizing the free memory space resulting from compressing the user data.

11. A storage device comprising:

a non-volatile memory; and

a controller in communication with the non-volatile memory, the controller configured to;

determine whether user data stored in a storage area in the memory is suitable for compression;

if it is determined that the user data is suitable for compression, compress the data; and

use free memory space resulting from compressing the user data for an internal storage device operation, wherein a capacity reported to a host device as being available for storing additional user data remains unchanged after compressing the user data, and wherein the free memory space is not used for additional user data.

12. The storage device of claim 11, wherein determining whether user data is suitable for compression comprises determining whether the user data is backup data.

13. The storage device of claim 11, wherein determining whether user data is suitable for compression comprises determining a compression efficiency for the user data.

14. The storage device of claim 11, wherein determining whether user data is suitable for compression comprises determining an access frequency of the user data.

15. The storage device of claim 11, wherein the controller is further operative to determine a compression algorithm to use to compress the user data.

16. The storage device of claim 11, wherein the controller is further operative to determine a schedule for compressing the user data.

17. The storage device of claim 11, wherein the controller is further operative to determine whether compressing the user data would violate a rule.

18. The storage device of claim 17, wherein the rule is violated if a logical partition is reformatted.

19. The storage device of claim 17, wherein the rule is violated if a change is made to user data that is frequently accessed or modified.

20. The storage device of claim 11, wherein the controller is further configured to monitor I/O transactions from the host device to determine if a rule is violated by utilizing the free memory space resulting from compressing the user data.