Host system and process to reduce declared capacity of a storage device by trimming

• US 9,563,362 B2
• Filed: 02/12/2015
• Issued: 02/07/2017
• Est. Priority Date: 09/02/2014
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Inventors: Samuels, Allen, Kruger, Warren Fritz, Truong, Linh Tien
• Primary Examiner(s): Nguyen, Than
• Application Number:
  US14/621,135
• Publication Number:
  US 20160062662A1
• Time in Patent Office: 726 Days
• Field of Search: 711/103, 711/170, 711/E12.009
• US Class Current: 1/1
• 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 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays

Abstract

Systems, methods, and/or devices are used to reduce declared capacity of non-volatile memory of a storage device in a storage system. In one aspect, the method includes, detecting an amelioration trigger for reducing declared capacity of non-volatile memory of the storage device of the storage system, and in accordance with the detected amelioration trigger, performing an amelioration process to reduce declared capacity of the non-volatile memory of the storage device, the performing including: trimming at least a portion of a set of logical addresses in a logical address space; and reducing declared capacity of the non-volatile memory of the storage device. In some embodiments, the storage device includes one or more flash memory devices. In some embodiments, the method is performed by a host to which a storage device of the storage system is operatively coupled.

Claims

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

at a host to which a storage device of the storage system is operatively coupled;

detecting an amelioration trigger for reducing declared capacity of non-volatile memory of the storage device of the storage system, wherein declared capacity is storage capacity available to the host;

in accordance with the detected amelioration trigger, performing an amelioration process to reduce declared capacity of the non-volatile memory of the storage device, the performing including;

trimming at least a portion of a set of logical addresses in a logical address space; and

reducing declared capacity of the non-volatile memory of the storage device;

prior to detecting the amelioration trigger, detecting a first wear condition of the non-volatile memory of the storage device, wherein a total storage capacity of the non-volatile memory of the 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 storage device without reducing declared capacity of the non-volatile memory of the storage device.

2. The method of claim 1, wherein detecting the amelioration trigger comprises detecting a second wear condition distinct from the first wear condition.

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

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

5. The method of claim 1, wherein trimming at least a portion of the set of logical addresses includes trimming at least a portion of the set of logical addresses in accordance with one or more parameters for the amelioration process.

6. The method of claim 1, wherein trimming at least a portion of the set of logical addresses includes:

obtaining information specifying the set of logical addresses in the logical address space; and

invalidating one or more logical address entries, associated with the set of logical addresses, of a mapping table, the mapping table used to translate logical addresses in the logical address space to physical addresses in a physical address space of the storage device.

7. The method of claim 6, wherein reducing declared capacity of the non-volatile memory of the storage device includes making a number of logical addresses, less than or equal to a number of logical addresses corresponding to the invalidated logical address entries, unavailable to the host.

8. The method of claim 1, wherein performing the amelioration process to reduce declared capacity of the non-volatile memory of the storage device further includes advertising a reduced declared capacity of the non-volatile memory of the storage device.

9. The method of claim 1, further comprising:

after beginning performance of the amelioration process to reduce declared capacity of the non-volatile memory of the storage device, detecting an indication to abort the reduction in declared capacity of the non-volatile memory of the storage device; and

in response to detecting the indication to abort the reduction in declared capacity of the non-volatile memory of the storage device, aborting performance of the amelioration process to reduce declared capacity of the non-volatile memory of the storage device.

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

11. A storage system, comprising:

one or more storage devices; and

a host to which the one or more storage devices are operatively coupled, the host including;

one or more processors; and

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

detecting an amelioration trigger for reducing declared capacity of non-volatile memory of a storage device of the storage system, wherein declared capacity is storage capacity available to the host;

in accordance with the detected amelioration trigger, performing an amelioration process to reduce declared capacity of the non-volatile memory of the storage device, the performing including;

trimming at least a portion of a set of logical addresses in a logical address space; and

reducing declared capacity of the non-volatile memory of the storage device;

prior to detecting the amelioration trigger, detecting a first wear condition of the non-volatile memory of the storage device, wherein a total storage capacity of the non-volatile memory of the 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 storage device without reducing declared capacity of the non-volatile memory of the storage device.

12. The storage system of claim 11, wherein trimming at least a portion of the set of logical addresses includes:

obtaining information specifying the set of logical addresses in the logical address space; and

invalidating one or more logical address entries, associated with the set of logical addresses, of a mapping table, the mapping table used to translate logical addresses in the logical address space to physical addresses in a physical address space of the storage device.

13. The storage system of claim 12, wherein reducing declared capacity of the non-volatile memory of the storage device includes making a number of logical addresses, less than or equal to a number of logical addresses corresponding to the invalidated logical address entries, unavailable to the host.

14. The storage system of claim 11, wherein detecting the amelioration trigger comprises detecting a second wear condition distinct from the first wear condition.

15. The storage system of claim 11, wherein the storage device comprises one or more flash memory devices.

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

detecting an amelioration trigger for reducing declared capacity of non-volatile memory of a storage device coupled to the host system, wherein declared capacity is storage capacity available to the host system;

in accordance with the detected amelioration trigger, performing an amelioration process to reduce declared capacity of the non-volatile memory of the storage device, the performing including;

trimming at least a portion of a set of logical addresses in a logical address space; and

reducing declared capacity of the non-volatile memory of the storage device;

prior to detecting the amelioration trigger, detecting a first wear condition of the non-volatile memory of the storage device, wherein a total storage capacity of the non-volatile memory of the 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 storage device without reducing declared capacity of the non-volatile memory of the storage device.

17. The non-transitory computer readable storage medium of claim 16, wherein trimming at least a portion of the set of logical addresses includes:

obtaining information specifying the set of logical addresses in the logical address space; and

invalidating one or more logical address entries, associated with the set of logical addresses, of a mapping table, the mapping table used to translate logical addresses in the logical address space to physical addresses in a physical address space of the storage device.

18. The non-transitory computer readable storage medium of claim 17, wherein reducing declared capacity of the non-volatile memory of the storage device includes making a number of logical addresses, less than or equal to a number of logical addresses corresponding to the invalidated logical address entries, unavailable to the host.

19. The non-transitory computer readable storage medium of claim 16, wherein detecting the amelioration trigger comprises detecting a second wear condition distinct from the first wear condition.

20. The non-transitory computer readable storage medium of claim 16, wherein the storage device comprises one or more flash memory devices.