Data storage system with dynamic erase block grouping mechanism and method of operation thereof

Patent metadata

Field	Value
Publication number	US-9665295-B2
Application number	US-201615249237-A
Country	US
Kind code	B2
Filing date	Aug 26, 2016
Priority date	Aug 7, 2013
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

Systems, methods and/or devices are used to enable dynamic erase block grouping. In one aspect, the method includes (1) maintaining metadata for each erase block of a plurality of erase blocks in a data storage system, wherein a respective metadata for a respective erase block includes one or more characteristics of the respective erase block, (2) allocating a set of erase blocks, of the plurality of erase blocks, as unassociated erase blocks, (3) selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics, and (4) grouping the two or more unassociated erase blocks with similar characteristics to form a super block.

First claim

What is claimed is:

1. A method of operation of a data storage system, the method comprising:
maintaining metadata for each erase block of a plurality of erase blocks in the data storage system, wherein a respective metadata for a respective erase block includes one or more characteristics of the respective erase block;
allocating a set of erase blocks, of the plurality of erase blocks, as unassociated erase blocks; and
forming a plurality of super blocks, including, for each super block to be formed:
selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics, wherein said characteristics of the unassociated erase blocks, in accordance with which the two or more unassociated erase blocks are selected, include at least one characteristic selected from the group consisting of age information, bit error rate, wear statistics, and operation parameters;
grouping the two or more selected erase blocks to form the super block;
aggregating metadata from the two or more selected erase blocks; and
storing the aggregated metadata as metadata for the super block.

2. The method of claim 1 , wherein the selecting includes enforcing a minimum amount of dwell time for the unassociated erase blocks, wherein dwell time is the amount of time between operations on a respective erase block.

3. The method of claim 1 , wherein the metadata is maintained in persistent storage in the data storage system.

4. The method of claim 1 , wherein the super block includes two or more unassociated erase blocks from different memory die of the data storage system.

5. The method of claim 1 , wherein selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics includes selecting two or more unassociated erase blocks with similar ages.

6. The method of claim 1 , wherein selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics includes:
selecting a first unassociated erase block from a first die of the data storage system;
selecting a second unassociated erase block from a second die of the data storage system; and
forgoing selection of a third unassociated erase block from a third die of the data storage system, wherein the third die is relatively worn in comparison to the first die and second die.

7. The method of claim 1 , further comprising:
selecting one or more erase blocks, in accordance with the one or more characteristics of the one or more erase blocks, for recycling;
recycling the selected one or more erase blocks; and
allocating the recycled one or more erase blocks as unassociated erase blocks.

8. The method of claim 1 , further comprising:
selecting, from the super block, a relatively old erase block to store parity information.

9. A data storage system, comprising:
one or more processors; and
memory storing one or more programs to be executed by the one or more processors, the one or more programs comprising instructions for:
maintaining metadata for each erase block of a plurality of erase blocks in the data storage system, wherein a respective metadata for a respective erase block includes one or more characteristics of the respective erase block;
allocating a set of erase blocks, of the plurality of erase blocks, as unassociated erase blocks; and
forming a plurality of super blocks, including, for each super block to be formed:
selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics, wherein said characteristics of the unassociated erase blocks, in accordance with which the two or more unassociated erase blocks are selected, include at least one characteristic selected from the group consisting of age information, bit error rate, wear statistics, and operation parameters;
grouping the two or more selected erase blocks to form the super block;
aggregating metadata from the two or more selected erase blocks; and
storing the aggregated metadata as metadata for the super block.

10. The data storage system of claim 9 , wherein selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics includes enforcing a minimum amount of dwell time for the unassociated erase blocks, wherein dwell time is the amount of time between operations on a respective erase block.

11. The data storage system of claim 9 , wherein the metadata is maintained in persistent storage in the data storage system.

12. The data storage system of claim 9 , wherein the super block includes two or more unassociated erase blocks from different memory die of the data storage system.

13. The data storage system of claim 9 , wherein selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics includes selecting two or more unassociated erase blocks with similar ages.

14. The data storage system of claim 9 , wherein selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics includes:
selecting a first unassociated erase block from a first die of the data storage system;
selecting a second unassociated erase block from a second die of the data storage system; and
forgoing selection of a third unassociated erase block from a third die of the data storage system, wherein the third die is relatively worn in comparison to the first die and second die.

15. The data storage system of claim 9 , wherein the one or more programs further comprise instructions for:
selecting one or more erase blocks, in accordance with the one or more characteristics of the one or more erase blocks, for recycling;
recycling the selected one or more erase blocks; and
allocating the recycled one or more erase blocks as unassociated erase blocks.

16. The data storage system of claim 9 , wherein the one or more programs further comprise instructions for selecting, from the super block, a relatively old erase block to store parity information.

17. A non-transitory computer readable storage medium, storing one or more programs configured for execution by one or more processors of a data storage system, the one or more programs including instructions for:
maintaining metadata for each erase block of a plurality of erase blocks in the data storage system, wherein a respective metadata for a respective erase block includes one or more characteristics of the respective erase block;
allocating a set of erase blocks, of the plurality of erase blocks, as unassociated erase blocks; and
forming a plurality of super blocks, including, for each super block to be formed:
selecting two or more unassociated erase blocks in accordance with characteristics of the unassociated erase blocks so as to select unassociated erase blocks with similar characteristics, wherein said characteristics of the unassociated erase blocks, in accordance with which the two or more unassociated erase blocks are selected, include at least one characteristic selected from the group consisting of age

Assignees

• Sandisk Technologies Llc

Inventors

• Fitzpatrick James
• Dancho Mark
• Higgins James M
• Ellis Robert W
• Rub Bernardo

Classifications

• G06F3/0679

  Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP] · CPC title

• G06F3/0616 Primary

  in relation to life time, e.g. increasing Mean Time Between Failures [MTBF] · CPC title

• G06F3/064

  Management of blocks · CPC title

• G11C16/16

  for erasing blocks, e.g. arrays, words, groups · CPC title

• G11C16/10

  Programming or data input circuits · CPC title