USING SPARE CAPACITY IN SOLID STATE DRIVES

• US 20150324262A1
• Filed: 08/20/2014
• Published: 11/12/2015
• Est. Priority Date: 05/06/2014
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Chinnakkonda Vidyapoornachary, Diyanesh B., Daly, David M., Tressler, Gary A.
• Granted Patent: US 9,495,248 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/108 Parity data distribution in semiconductor storages, e.g. in SSD
• CPC Class Codes: G06F 11/1088 Reconstruction on already foreseen single or plurality of spare disks
• CPC Class Codes: G06F 11/2041 with more than one idle spare processing component
• CPC Class Codes: G06F 11/2058 using more than 2 mirrored copies
• CPC Class Codes: G06F 11/2084 on the same storage unit
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 2201/805 Real-time
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the 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 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0658 Controller construction arrangements
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]

Abstract

An SSD has a plurality of dies, with each die having a storage capacity. The storage capacity of each die is divided into a primary capacity and a spare capacity. A primary die has a maximum primary capacity, and a sum of the spare capacities of the remaining dies is greater than the maximum primary capacity. Data stored on the SSD is distributed among the primary capacities of the dies. When a failure of a first die is detected, data stored on the failed first die is migrated to the spare capacity of at least one of the remaining dies.

Claims

1. A method for managing the storage of data on a solid state drive (SSD), the SSD having a plurality of dies, each die of the plurality of dies having a storage capacity, the method comprising:

dividing the storage capacity of each die of the plurality of dies into a primary capacity and a spare capacity, a primary die of the plurality of dies having a maximum primary capacity, a sum of the spare capacities of each of the plurality of dies excluding the primary die being at least as great as the maximum primary capacity;

storing the data on the SSD, the stored data distributed among each of the primary capacities, a first portion of the data stored in the primary capacity of a first die of the plurality of dies;

detecting a failure of the first die; and

in response to the detecting the failure of the first die, migrating the first portion of the data to the spare capacity of at least one of the plurality of dies.

2. The method of claim 1, wherein each die of the plurality of dies has a first plurality of blocks allocated as the primary capacity and a second plurality of blocks allocated as the spare capacity, the method further comprising:

detecting a failure of a first block of the first plurality of blocks of the primary capacity of one of the plurality of dies; and

in response to the detecting the failure of the first block, migrating data stored on the first block to a second block of the second plurality of blocks of the spare capacity of one of the plurality of dies.

3. The method of claim 2, wherein, the detecting the failure of the first block occurs prior to the detecting the failure of the first die.

4. The method of claim 2, further comprising:

detecting a failure of a third block of the plurality of blocks of the primary capacity of one of the plurality of dies; and

in response to the detecting the failure of the third block, migrating data stored on the third block to a fourth block of the second plurality of blocks of the spare capacity of one of the plurality of dies.

5. The method of claim 4, wherein the detecting the failure of the third block occurs subsequent to the detecting the failure of the first die.

6. The method of claim 1, wherein a second portion of the data is stored in the primary capacity of a second die of the plurality of dies, the method further comprising:

subsequent to the failure of the first die, detecting a failure of the second die; and

in response to the detecting the failure of the second die, migrating the second portion of the data to the spare capacity of at least one die of the plurality of dies.

7. The method of claim 1, wherein the at least one of the plurality of dies is at least two of the plurality of dies.

8. The method of claim 1, wherein after the detecting the failure of the first die, the plurality of dies includes at least three non-failed dies, and wherein the at least one of the plurality of dies is all of the at least three non-failed dies.

9. The method of claim 2, wherein the first block is located on a second die of the plurality of dies, and wherein the second block is located on a third die of the plurality of dies.

10. The method of claim 1, wherein the primary capacity of each die of the plurality of dies equals the maximum primary capacity.

11. The method of claim 1, wherein:

a total primary capacity of the SSD equals a sum of the primary capacities of each of the plurality of dies; and

a total spare capacity of the SSD equals the sum of the spare capacities of each of the plurality of dies.

12. The method of claim 1, wherein the SSD is a 3D flash based SSD.