Multiple-Stage Data Lifetime Management for Storage Devices

• US 20190179559A1
• Filed: 02/22/2018
• Published: 06/13/2019
• Est. Priority Date: 12/07/2017
• Status: Active Grant

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Inventors: Bolkhovitin, Vladislav, Subbarao, Sanjay, O'Krafka, Brian W., Kulkarni, Anand
• Granted Patent: US 10,642,525 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 12/02 Addressing or allocation; Relocation program address sequencing G06F9/00; arrangements for selecting an address in a digital store G11C8/00
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0253 Garbage collection, i.e. reclamation of unreferenced memory
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 2212/7207 management of metadata or control data
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0649 Lifecycle management
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

A main controller in a data storage system having multiple storage devices determines an initial set of memory block candidates for data lifetime operations by receiving from each of a plurality of the storage devices information identifying one or more potential memory block candidates, with respective received memory blocks having been classified by respective storage devices as potential candidates. The main controller determines a set of related memory blocks, and, based on received usage information for the candidate memory blocks and the related memory blocks, selects a target group of memory blocks and initiates performance of the data lifetime operations on the memory blocks of the selected target group.

Claims

1. A method of managing data lifetime in a multi-device storage environment comprising:

at a main controller;

determining an initial set of memory block candidates, including receiving from each of a plurality of storage devices of the multi-device storage environment, information identifying one or more memory block candidates, wherein each memory block candidate of the identified memory block candidates is located in a respective storage device of the plurality of storage devices and has been determined by the respective storage device to be a candidate for a management operation;

determining a set of related memory blocks, related to the initial set of memory block candidates in accordance with predefined groups of memory blocks;

receiving usage information for the initial set of memory block candidates and the set of related memory blocks;

selecting a target group of memory blocks of the predefined groups of memory blocks based on the received usage information for the initial set of memory block candidates and set of related memory blocks; and

initiating performance of the management operation on the selected target group of memory blocks.

2. The method of claim 1, wherein each predefined group of memory blocks includes memory blocks in two or more data storage devices in the multi-device storage environment.

3. The method of claim 1, wherein each predefined group of memory blocks comprises a distinct superblock in a set of superblocks, wherein each superblock in the set of superblocks is a minimum size unit of memory for performing the management operation.

4. The method of claim 1, wherein the received usage information includes usage information for individual respective memory blocks and data storage device health information for the two or more data storage devices.

5. The method of claim 1, wherein the management operation is a garbage collection operation, a data compaction operation, a read disturb handling operation, or a data scrubbing operation.

6. The method of claim 1, wherein determining the set of related memory blocks includes identifying groups of memory blocks, in the predefined groups of memory blocks, that include the initial set of memory block candidates, and identifying, as the set of related memory blocks, memory blocks in the identified groups of memory blocks that are not included in the initial set of memory blocks.

7. The method of claim 1, wherein receiving the usage information includes sending a command to each of the plurality of storage devices, each respective command including a request for usage information for memory block candidates and related memory blocks located in the respective storage device.

8. The method of claim 1, wherein the target group selection is based on an evaluation of data lifetime management criteria.

9. The method of claim 8, wherein the data lifetime management criteria includes garbage collection selection criteria, the garbage collection selection criteria including criteria with respect to quantities of valid data, or invalid data, in the identified groups of memory blocks.

10. The method of claim 8, wherein the data lifetime management criteria includes read disturb selection criteria, the read disturb selection criteria including criteria with respect to read counts in the identified groups of memory blocks.

11. The method of claim 1, further comprising initiating a parity rebuild on the selected target group of memory blocks.

12. The method of claim 1, wherein each of the memory blocks in the one or more memory block candidates and set of related memory blocks is a partial page, a page, a set of multiple pages smaller than an erase block, an erase block, or set of two or more erase blocks.

13. The method of claim 1, wherein the main controller is implemented by a host system, wherein the host system also stores and accesses data in the plurality of storage devices.

14. The method of claim 1, wherein the main controller is implemented by a storage device in the multi-device storage environment.

15. The method of claim 1, wherein the main controller is a controller system distinct from and external to the plurality of storage devices.

16. The method of claim 15, wherein:

the main controller includes a host interface to receive host commands from one or more host systems external to the main controller, the host commands including host data access commands for storing and retrieving data; and

the main controller is configured, in response to receipt of the host data access commands, to generate and send corresponding data storage commands to respective storage devices of the plurality of storage devices so as to store data in and retrieve data from the plurality of storage devices in accordance with the host data access commands.

17. A system for managing data lifetime in a multi-device storage environment comprising:

a storage device interface for sending commands to and receiving responses from a plurality of storage devices;

controller system memory; and

one or more processors, the one or more processors configured to execute one or more programs stored in the controller system memory, the one or more programs including instructions for;

determining an initial set of memory block candidates, including receiving, via the storage device interface, from each of a plurality of storage devices of the multi-device storage environment, information identifying one or more memory block candidates, wherein each memory block candidate of the identified memory block candidates is located in a respective storage device of the plurality of storage devices and has been determined by the respective storage device to be a candidate for a management operation;

determining a set of related memory blocks, related to the initial set of memory block candidates in accordance with predefined groups of memory blocks;

receiving, via the storage device interface, usage information for the initial set of memory block candidates and the set of related memory blocks;

selecting a target group of memory blocks of the predefined groups of memory blocks based on the received usage information for the initial set of memory block candidates and set of related memory blocks; and

initiating performance of the management operation on the selected target group of memory blocks.

18. The system of claim 17, further comprising:

a host interface for receiving host data access commands from one or more hosts.

19. The system of claim 18,

wherein the host data access commands are for storing and retrieving data, and the one or more programs include instructions for, in response to receipt of the host data access commands, generating and sending corresponding data storage commands to respective storage devices of the plurality of storage devices so as to store data in and retrieve data from the plurality of storage devices in accordance with the host data access commands.

20. The system of claim 17, wherein each predefined group of memory blocks includes memory blocks in two or more data storage devices in the multi-device storage environment.

21. The system of claim 17, wherein each predefined group of memory blocks comprises a distinct superblock in a set of superblocks, wherein each superblock in the set of superblocks is a minimum size unit of memory for performing the management operation.