Notification of Trigger Condition to Reduce Declared Capacity of a Storage Device in a Multi-Storage-Device Storage System

• US 20160062699A1
• Filed: 02/12/2015
• Published: 03/03/2016
• Est. Priority Date: 09/02/2014
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Samuels, Allen, Kruger, Warren Fritz, Truong, Linh Tien
• Granted Patent: US 9,582,220 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/7204 Capacity control, e.g. partitioning, end-of-life degradation
• CPC Class Codes: G06F 2212/7205 Cleaning, compaction, garbage collection, erase control
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0634 by changing the state or mode of one or more devices
• CPC Class Codes: G06F 3/0649 Lifecycle management
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

Systems, methods and/or devices are used to enable notification of a trigger condition to reduce declared capacity of a storage device in a multi-storage-device storage system. In one aspect, the method includes: (1) obtaining, for each storage device of a plurality of storage devices, one or more metrics of the storage device, the storage device including non-volatile memory, (2) detecting a trigger condition for reducing declared capacity of the non-volatile memory of a respective storage device of the plurality of storage devices, the trigger condition detected in accordance with the one or more metrics of two or more of the storage devices, and (3) notifying a host of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device, the trigger condition for enabling performance of an amelioration process to reduce declared capacity of the non-volatile memory of the respective storage device.

Claims

1. A method of managing a storage system, the method comprising:

obtaining, for each storage device of a plurality of storage devices of the storage system, one or more metrics of the storage device, the storage device including non-volatile memory;

detecting a trigger condition for reducing declared capacity of the non-volatile memory of a respective storage device of the plurality of storage devices of the storage system, the trigger condition detected in accordance with the one or more metrics of two or more of the storage devices of the plurality of storage devices in the storage system; and

notifying a host to which the respective storage device is operatively coupled of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device, the trigger condition for enabling performance of an amelioration process to reduce declared capacity of the non-volatile memory of the respective storage device.

2. The method of claim 1, further comprising:

prior to detecting the trigger condition, detecting a first wear condition of the non-volatile memory of the respective storage device, wherein a total storage capacity of the non-volatile memory of the respective storage device includes declared capacity and over-provisioning; and

in response to detecting the first wear condition, performing a remedial action that reduces over-provisioning of the non-volatile memory of the respective storage device without reducing declared capacity of the non-volatile memory of the respective storage device.

3. The method of claim 2, wherein detecting the trigger condition comprises detecting a second wear condition distinct from the first wear condition.

4. The method of claim 1, wherein the host includes a client on behalf of which data is stored in the storage system.

5. The method of claim 1, wherein the host includes a storage system controller of the storage system.

6. The method of claim 1, wherein the host includes a cluster controller of the storage system.

7. The method of claim 1, wherein notifying the host of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device includes notifying the host with an unsolicited communication.

8. The method of claim 1, wherein notifying the host of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device includes:

receiving a query from the host; and

in response to receiving the query, reporting the trigger condition.

9. The method of claim 1, wherein notifying the host of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device includes:

receiving a command from the host; and

in response to receiving the command, sending a response to the command and a notification of the trigger condition.

10. The method of claim 1, wherein notifying the host of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device includes:

receiving a command from the host; and

in response to receiving the command, sending a response to the command and a notification that prompts the host to obtain information with respect to the trigger condition.

11. The method of claim 1, wherein notifying the host of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device includes notifying the host that the respective storage device is in read-only mode.

12. The method of claim 1, further comprising:

after notifying the host of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device;

re-evaluating the trigger condition in accordance with the one or more metrics of the two or more storage devices of the plurality of storage devices in the storage system; and

in accordance with a determination that the trigger condition is no longer valid, notifying the host of an absence of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device.

13. The method of claim 1, wherein the obtaining, the notifying, or both the obtaining and the notifying are performed by one or more subsystems of the storage system distinct from the plurality of storage devices.

14. The method of claim 1, wherein the amelioration process to reduce declared capacity of the non-volatile memory of the respective storage device includes a process to reduce utilization of the non-volatile memory of the respective storage device.

15. The method of claim 1, wherein the respective storage device comprises one or more flash memory devices.

16. A storage system, comprising:

non-volatile memory;

one or more processors; and

controller memory storing one or more programs, which when executed by the one or more processors cause the storage system to perform operations comprising;

obtaining, for each storage device of a plurality of storage devices of the storage system, one or more metrics of the storage device, the storage device including non-volatile memory;

detecting a trigger condition for reducing declared capacity of the non-volatile memory of a respective storage device of the plurality of storage devices of the storage system, the trigger condition detected in accordance with the one or more metrics of the respective storage device; and

notifying a host to which the respective storage device is operatively coupled of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device, the trigger condition associated with an amelioration process to reduce declared capacity of the non-volatile memory of the respective storage device.

17. The storage system of claim 16, wherein the one or more programs further include instructions that, when executed by the one or more processors, cause the storage system to perform operations comprising:

prior to detecting the trigger condition, detecting a first wear condition of the non-volatile memory of the respective storage device, wherein a total storage capacity of the non-volatile memory of the respective storage device includes declared capacity and over-provisioning; and

in response to detecting the first wear condition, performing a remedial action that reduces over-provisioning of the non-volatile memory of the respective storage device without reducing declared capacity of the non-volatile memory of the respective storage device.

18. A non-transitory computer readable storage medium, storing one or more programs configured for execution by one or more processors of a storage system, the one or more programs including instructions for:

obtaining, for each storage device of a plurality of storage devices of the storage system, one or more metrics of the storage device, the storage device including non-volatile memory;

detecting a trigger condition for reducing declared capacity of the non-volatile memory of a respective storage device of the plurality of storage devices of the storage system, the trigger condition detected in accordance with the one or more metrics of two or more of the storage devices of the plurality of storage devices in the storage system; and

notifying a host to which the respective storage device is operatively coupled of the trigger condition for reducing declared capacity of the non-volatile memory of the respective storage device, the trigger condition for enabling performance of an amelioration process to reduce declared capacity of the non-volatile memory of the respective storage device.

19. The non-transitory computer readable storage medium of claim 18, wherein the one or more programs further include instructions for:

prior to detecting the trigger condition, detecting a first wear condition of the non-volatile memory of the respective storage device, wherein a total storage capacity of the non-volatile memory of the respective storage device includes declared capacity and over-provisioning; and

in response to detecting the first wear condition, performing a remedial action that reduces over-provisioning of the non-volatile memory of the respective storage device without reducing declared capacity of the non-volatile memory of the respective storage device.