System, method, and computer program product for increasing spare space in memory to extend a lifetime of the memory

• US 10,318,181 B2
• Filed: 03/29/2017
• Issued: 06/11/2019
• Est. Priority Date: 11/28/2007
• Status: Active Grant

• Current Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Original Assignee: Seagate Technology LLC (Seagate Technology Holdings Plc)
• Inventors: Danilak, Radoslav
• Primary Examiner(s): Dudek, Jr., Edward J
• Application Number:
  US15/472,878
• Publication Number:
  US 20170199682A1
• Time in Patent Office: 804 Days
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 2212/1036 Life time enhancement
• CPC Class Codes: G06F 2212/1044 Space efficiency improvement
• CPC Class Codes: G06F 2212/401 Compressed data
• 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 2212/7206 Reconfiguration of flash memory system
• 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 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

Methods, systems and computer-readable storage media for increasing spare space in a storage subsystem including a flash memory, extending a lifetime of the storage subsystem to achieve a stored selected minimum lifetime based at least in part as a result of the increasing spare space, and identifying at least one aspect associated with the lifetime of the storage subsystem. The storage subsystem may include compressed data stored in the flash memory.

Claims

1. A storage system comprising:

a storage subsystem comprising a flash memory; and

a storage controller communicatively coupled to the flash memory, the storage controller configured to

identify a minimum desired lifetime of the flash memory;

receive a command for the storage subsystem;

determine whether the command is a lifetime-reducing command;

upon determining that the command is a lifetime-reducing command, compute an estimated lifetime of the flash memory based on the command received, a previous lifetime, and a current time;

determine whether the estimated lifetime is less than the minimum desired lifetime; and

upon determine that the estimated lifetime is less than the minimum desired lifetime, delay execution of the command.

2. The storage system of claim 1, wherein the flash memory comprises a plurality of blocks, and wherein the storage controller is further configured to:

equalize an end of life of the plurality of blocks; and

increase a spare space in the storage subsystem by removing duplicate data stored in the flash memory.

3. The storage system of claim 1, wherein the storage controller is further configured to:

identify a maximum average operation rate;

monitor a number of lifetime-reducing operations over time; and

upon determining that the number of lifetime-reducing operations over time exceeds the maximum average operation rate, delay the operations that contribute to exceeding the maximum average operation rate.

4. The storage system of claim 1, wherein operations received by the storage controller from applications with a lower priority may be subject to delay, while operations received by the storage controller from applications with a higher priority may not be subject to delay.

5. The storage system of claim 1, further comprising a plurality of storage subsystems communicatively coupled to storage controller, the storage controller further configured to move data between the plurality of storage subsystems based upon the minimum desired lifetime of the flash memory associated with each of the plurality of storage subsystems.

6. A method comprising:

identifying a minimum desired lifetime of a storage subsystem comprising a flash memory;

receiving a command for the storage subsystem from a computer;

determining whether the command is a lifetime-reducing command;

upon determining that the command is a lifetime-reducing command, computing an estimated lifetime of the flash memory based on at least the command received;

determining whether the estimated lifetime is less than the minimum desired lifetime; and

upon determining that the estimated lifetime is less than the minimum desired lifetime, delaying execution of the command.

7. The method of claim 6, wherein the flash memory comprises a plurality of blocks, the method further comprising:

equalizing an end of life of the plurality of blocks; and

increasing a spare space in the storage subsystem by removing duplicate data stored in the flash memory.

8. The method of claim 6, wherein the flash memory includes at least one of a single-bit per cell NOR flash memory, a multi-bit per cell NOR flash memory, a single-bit per cell NAND flash memory, and a multi-bit per cell NAND flash memory.

9. The method of claim 6, further comprising:

identifying a maximum average operation rate;

monitoring a number of lifetime-reducing operations over time; and

upon determining that the number of lifetime-reducing operations over time exceeds the maximum average operation rate, delaying the operations that contribute to exceeding the maximum average operation rate.

10. A non-transitory computer readable storage medium having processor-executable instructions stored thereon that, when executed by a processor of a storage controller, cause the processor to:

identify a minimum desired lifetime of a storage subsystem controlled by the storage controller, the storage subsystem comprising a flash memory;

receive a command for the storage subsystem;

determine whether the command is a lifetime-reducing command;

upon determining that the command is a lifetime-reducing command, compute an estimated lifetime of the flash memory based on the command received, a previous lifetime, and a current time;

determine whether the estimated lifetime is less than the minimum desired lifetime; and

upon determine that the estimated lifetime is less than the minimum desired lifetime, delay execution of the command.

11. The non-transitory computer readable storage medium of claim 10, wherein the flash memory comprises a plurality of blocks and wherein the processor is further configured to:

equalize an end of life of the plurality of blocks; and

increase a spare space in the storage subsystem by removing duplicate data stored in the flash memory.