METHOD TO LIMIT IMPACT OF PARTIAL MEDIA FAILURE OF DISK DRIVE AND DETECT/REPORT THE LOSS OF DATA FOR OBJECTS DUE TO PARTIAL FAILURE OF MEDIA

• US 20170277451A1
• Filed: 03/22/2016
• Published: 09/28/2017
• Est. Priority Date: 03/22/2016
• Status: Active Grant

• Current Assignee: Kioxia Corporation
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: GOLE, Abhijeet, JOSHI, Ratnadeep, KUFELDT, Philip A.
• Granted Patent: US 10,642,508 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 11/004 Error avoidance G06F11/07 and subgroups take precedence
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0676 Magnetic disk device

Abstract

Object data, such as a key-value pair, are stored in a disk drive in conjunction with metadata associated with the object data. A key-value pair and metadata associated therewith are written in different locations in the disk drive, but as part of a single sequential write operation, such as when contents of a key-value buffer containing one or more key-value pairs are flushed to the disk drive. The key-value pair may be written during a first phase of the sequential write operation and the metadata may be written during a second phase of the sequential write operation that does not immediately precede or follow the first phase.

Claims

1. A method of storing contents of a key-value buffer into one of multiple regions of at least one disk drive in a single sequential write process, the method comprising the steps of:

determining that a used capacity of the key-value buffer is greater than a threshold capacity;

writing first and second key-value pairs in the key-value buffer to first and second physical locations in one of the regions, respectively; and

writing metadata that indicates the first and second physical locations as the storage location for the first and second key-value pairs, respectively, in a third physical location in the region.

2. The method of claim 1, wherein contents of the first and third physical locations are not written consecutively in the single sequential write process.

3. The method of claim 1, wherein contents of the first and second physical locations are written consecutively in the single sequential write process.

4. The method of claim 1, wherein the single sequential write process includes writing the first and second key-value pairs to the first and second physical locations, respectively, and writing the metadata in the third physical location.

5. The method of claim 1, further comprising:

receiving the first and second key-value pairs; and

storing the received first and second key-value pairs in the key-value buffer.

6. The method of claim 1, further comprising:

receiving a third key-value pair for storage in the at least one disk drive;

storing the third key-value pair in the key-value buffer; and

determining a fourth physical location in the region for storing the third key-value pair and a fifth physical location in the region for storing metadata associated with the third key-value pair.

7. The method of claim 6, wherein the metadata indicates the fourth physical location as the storage location in the region for the third key-value pair.

8. The method of claim 7, further comprising:

writing the third key-value pair in the key-value buffer to the fourth physical location; and

writing the metadata associated with the third key-value pair in the fifth physical location.

9. The method of claim 8, wherein the single sequential write process includes writing the third key-value pair to the fourth physical location and writing the metadata associated with the third key-value pair in the fifth physical location.

10. The method of claim 6, wherein, in the single sequential write process, contents of the fourth physical location are not written consecutively with contents of the first physical location or the second physical location.

11. The method of claim 10, wherein, in the single sequential write process, contents of the first and second physical locations are written consecutively.

12. The method of claim 10, wherein the third key-value pair is the key-value pair received directly after the first key-value pair.

13. The method of claim 1, wherein, in the single sequential write process, the metadata are written in the third physical location before the first and second key-value pairs are respectively written to the first and second physical locations.

14. The method of claim 1, wherein, in the single sequential write process, the metadata are written in the third physical location after the first and second key-value pairs are respectively written to the first and second physical locations.

15. A method of retrieving data from a data storage system that repeatedly moves contents of a key-value buffer into one of multiple regions of at least one disk drive in a single sequential write process, the method comprising the steps of:

receiving, from a disk drive of the data storage system, a read-error message in response to a read that targets a first physical location in one of the regions;

responsive to the read-error message, issuing a read that targets a second physical location in the region, the second physical location storing metadata that indicates physical locations of key-value pairs that are stored within the first physical location; and

determining, based on the metadata, a key associated with the first physical location.

16. The method of claim 15, wherein the contents of the first and second physical locations are not written consecutively in the single sequential write process.

17. The method of claim 16, further comprising, responsive to the read-error message, issuing a read that targets a third physical location in the region, wherein the third physical location is distinct from the first physical location and stores one or more additional key-value pairs.

18. The method of claim 17, further comprising:

receiving, from the disk drive, an additional read-error message in response to the read that targets the third physical location; and

responsive to the additional read-error message, issuing a read that targets a fourth physical location in the region, the fourth physical location storing metadata that indicates physical locations of key-value pairs that are stored within the third physical location; and

determining, based on the metadata, a key associated with the third physical location.

19. The method of claim 17, wherein, in a single sequential write process, contents of the third physical location are written before contents are written to the first physical location.

20. The method of claim 17, wherein, in a single sequential write process, contents of the third physical location are written after contents are written to the first physical location.

21. The method of claim 17, wherein contents of the third physical location comprise the next key-value pair written in the single sequential write process directly after contents are written to the first physical location in the single sequential write process.