Variable Over-Provisioning For Non-Volatile Storage

• US 20140101379A1
• Filed: 04/22/2012
• Published: 04/10/2014
• Est. Priority Date: 04/26/2011
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: LSI Corporation (Broadcom, Inc.)
• Inventors: Tomlin, Andrew John
• Granted Patent: US 10,241,908 B2
• Time in Patent Office: Days
• US Class Current: 711/103
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/214 Solid state disk
• CPC Class Codes: G06F 2212/7202 Allocation control and policies
• CPC Class Codes: G06F 2212/7204 Capacity control, e.g. partitioning, end-of-life degradation
• CPC Class Codes: G06F 2212/7206 Reconfiguration of flash memory system
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

Dynamically varying Over-Provisioning (OP) enables improvements in lifetime, reliability, and/or performance of a Solid-State Disk (SSD) and/or a flash memory therein. A host coupled to the SSD writes newer data to the SSD. If the newer host data is less random than older host data, then entropy of host data on the SSD decreases. In response, an SSD controller of the SSD dynamically alters allocations of the flash memory, decreasing host allocation and increasing OP allocation. If the newer host data is more random, then the SSD controller dynamically increases the host allocation and decreases the OP allocation. The SSD controller dynamically allocates the OP allocation between host OP and system OP proportionally in accordance with a ratio of bandwidths of host and system data writes to the flash memory.

Claims

1. A system comprising:

a means for operating all or any portions of one or more flash memories as respective allocations dedicated respectively to host data, system data, system over-provisioning (OP), and host OP;

a means for dynamically determining any one or more of the respective allocations in response to one or more events;

wherein the means for operating and the means for dynamically determining are comprised in a controller of a Solid-State Disk (SSD) and the flash memories are comprised in the SSD; and

wherein the events comprise a change in a used amount of the host data allocation due at least in part to a change in compression of host data stored in the host data allocation.

2. The system of claim 1, wherein the means for dynamically determining increases one or more of the system data allocation and the system OP allocation in response to a reduction in the used amount of the host data allocation due to improved compression of the used amount of the host data allocation.

3. The system of claim 1, wherein the means for dynamically determining increases one or more of the system OP allocation and the host OP allocation in response to a reduction in the used amount of the host data allocation due to improved compression of the used amount of the host data allocation.

4. The system of claim 3, wherein the means for dynamically determining allocates between the system OP allocation and the host OP allocation based at least in part on respective bandwidths of writes to the system data allocation and to the host data allocation.

5. The system of claim 1, wherein the change in compression is determined at least in part by determining a change in amount of the host data allocation that is unused.

6. The system of claim 1, wherein the change in the used amount of the host data allocation is due at least in part to a change in deduplication of the stored host data.

7. The system of claim 1, wherein the change in the used amount of the host data allocation is due at least in part to a host command that explicitly de-allocates all or any portions of the stored host data.

8. The system of claim 1, wherein changes to any one or more of the respective allocations is effective any one or more of immediately, after garbage collecting, after recycling, and after erasing.

9. The system of claim 1, further comprising a means for interfacing with a host, the means for interfacing comprised in the controller and enabled to receive data from the host.

10. A method comprising:

operating all or any portions of one or more flash memories as respective allocations dedicated respectively to host data, system data, system over-provisioning (OP), and host OP;

dynamically determining any one or more of the respective allocations in response to one or more events;

wherein the operating and the dynamically determining are performed by a controller comprised in a Solid-State Disk (SSD); and

wherein the events comprise a change in a used amount of the host data allocation due at least in part to a change in compression of host data stored in the host data allocation.

11. The method of claim 10, wherein the dynamically determining increases one or more of the system data allocation and the system OP allocation in response to a reduction in the used amount of the host data allocation due to improved compression of the used amount of the host data allocation.

12. The method of claim 10, wherein the dynamically determining increases one or more of the system OP allocation and the host OP allocation in response to a reduction in the used amount of the host data allocation due to improved compression of the used amount of the host data allocation, and allocates between the system OP allocation and the host OP allocation based at least in part on respective bandwidths of writes to the system data allocation and to the host data allocation.

13. The method of claim 10, wherein the change in compression is determined at least in part by determining a change in amount of the host data allocation that is unused.

14. The method of claim 10, wherein the change in the used amount of the host data allocation is due at least in part to one or more of a change in deduplication of the stored host data and a host command that explicitly de-allocates all or any portions of the stored host data.

15. The method of claim 10, wherein changes to any one or more of the respective allocations is effective any one or more of immediately, after garbage collecting, after recycling, and after erasing.

16. A tangible computer readable medium having a set of instructions stored therein that when executed by a processing element cause the processing element to perform and/or control operations comprising:

managing all or any portions of one or more flash memories as respective allocations dedicated respectively to host data, system data, system over-provisioning (OP), and host OP;

dynamically determining any one or more of the respective allocations in response to one or more events;

wherein the tangible computer readable medium and the processing element are comprised in a Solid-State Disk (SSD); and

wherein the events comprise a change in a used amount of the host data allocation due at least in part to a change in compression of host data stored in the host data allocation.

17. The tangible computer readable medium of claim 16, wherein the dynamically determining increases one or more of the system OP allocation and the host OP allocation in response to a reduction in the used amount of the host data allocation due to improved compression of the used amount of the host data allocation, and allocates between the system OP allocation and the host OP allocation based at least in part on respective bandwidths of writes to the system data allocation and to the host data allocation.

18. The tangible computer readable medium of claim 16, wherein the change in compression is determined at least in part by determining a change in amount of the host data allocation that is unused.

19. The tangible computer readable medium of claim 16, wherein the change in the used amount of the host data allocation is due at least in part to one or more of a change in deduplication of the stored host data and a host command that explicitly de-allocates all or any portions of the stored host data.

20. The tangible computer readable medium of claim 16, wherein changes to any one or more of the respective allocations is effective any one or more of immediately, after garbage collecting, after recycling, and after erasing.