Method and system for implementing multi-dimensional raid in an extensible storage array to optimize performance

• US 10,289,491 B1
• Filed: 04/28/2017
• Issued: 05/14/2019
• Est. Priority Date: 04/28/2017
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Ho, Grace, Yarbrough, James
• Primary Examiner(s): Le, Dieu Minh T
• Application Number:
  US15/581,431
• Time in Patent Office: 746 Days
• Field of Search: 714 624, 714 61, 714 611, 714 612, 714 613, 714 62, 714 621, 714 622, 714 623, 714 63
• CPC Class Codes: G06F 11/1096 Parity calculation or recalculation after configuration or reconfiguration of the system
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 2201/85 Active fault masking without idle spares active fault masking without idle spare hardware where processing functionality is redundant G06F11/2035
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0658 Controller construction arrangements
• CPC Class Codes: G06F 3/0685 Hybrid storage combining heterogeneous device types, e.g. hierarchical storage, hybrid arrays
• CPC Class Codes: G06F 3/0688 Non-volatile semiconductor memory arrays

Abstract

In general, embodiments of the technology relate to a method for storing data. More specifically, the method may include selecting a first RAID grid location in a RAID grid, where the first RAID grid location is flagged, selecting a second RAID grid location in the RAID grid, making a first determination that the second RAID grid location is not flagged, in response to the first determination, loading first data associated with the second RAID grid location into a cache, calculating a parity value for a corresponding set of RAID grid locations in a data grid using the first data in the cache, where the first RAID grid location and the second RAID grid location are in the set of RAID grid locations, and storing at least a copy of the first data and the parity value in a storage array comprising persistent storage.

Claims

1. A method for storing data comprising:

selecting a first RAID grid location in a RAID grid, wherein the first RAID grid location is flagged;

selecting a second RAID grid location in the RAID grid;

making a first determination that the second RAID grid location is not flagged;

in response to the first determination, loading first data associated with the second RAID grid location into a cache;

calculating a parity value for a corresponding set of RAID grid locations in a data grid using the first data in the cache, wherein the first RAID grid location and the second RAID grid location are in the set of RAID grid locations; and

storing at least a copy of the first data and the parity value in a storage array comprising persistent storage;

wherein prior to selecting the first RAID grid location;

identifying a set of storage modules that are present in the storage array;

making a second determination that at least one storage module is not present in the storage array;

in response to the second determination;

specifying that the first RAID grid location is a RAID grid location that is not associated with any of the set of storage modules; and

in response to the specifying, associating the first RAID grid location with a flag.

2. The method of claim 1, further comprising:

selecting a third RAID grid location in the RAID grid

making a second determination that the third RAID grid location is flagged;

in response to the second determination, generating tracking information specifying that the third RAID grid location is flagged;

selecting a fourth RAID grid location in the RAID grid;

making a third determination that the fourth RAID grid location is not flagged;

in response to the third determination, loading third data associated with the fourth RAID grid location into the cache;

calculating a second parity value for a corresponding second set of RAID grid locations in the data grid using the second data in the cache and the tracking information, wherein the third RAID grid location and the fourth RAID grid location are in the second set of RAID grid locations; and

storing at least a copy of the second data and the second parity value in the storage.

3. The method of claim 2, wherein the second parity value is a Q parity value.

4. The method of claim 1, wherein the second RAID grid location is associated with a physical location in a storage module of the set of storage modules in the storage array.

5. The method of claim 1, wherein the first parity value is a P parity value.

6. The method of claim 1, wherein the persistent storage is solid state memory.

7. A non-transitory computer readable medium comprising computer readable program code, which when executed by a computer processor enables the computer processor to:

select a first RAID grid location in a RAID grid, wherein the first RAID grid location is flagged;

select a second RAID grid location in the RAID grid;

make a first determination that the second RAID grid location is not flagged;

in response to the first determination, load first data associated with the second RAID grid location into a cache;

calculate a parity value for a corresponding set of RAID grid locations in a data grid using the first data in the cache, wherein the first RAID grid location and the second RAID grid location are in the set of RAID grid locations; and

store at least a copy of the first data and the parity value in a storage array comprising persistent storage;

wherein prior to selecting the first RAID grid location;

identify a set of storage modules that are present in the storage array;

make a second determination that at least one storage module is not present in the storage array;

in response to the second determination,

specify that the first RAID grid location is a RAID grid location that is not associated with any of the set of storage modules; and

in response to the specifying, associate the first RAID grid location with a flag.

8. The non-transitory computer readable medium of claim 7 further comprising computer readable program code, which when executed by the computer processor enables the computer processor to:

select a third RAID grid location in the RAID grid;

make a second determination that the third RAID grid location is flagged;

in response to the second determination, generate tracking information specifying that the third RAID grid location is flagged;

select a fourth RAID grid location in the RAID grid;

make a third determination that the fourth RAID grid location is not flagged;

in response to the third determination, load third data associated with the fourth RAID grid location into the cache;

calculate a second parity value for a corresponding second set of RAID grid locations in the data grid using the second data in the cache and the tracking information, wherein the third RAID grid location and the fourth RAID grid location are in the second set of RAID grid locations; and

store at least a copy of the second data and the second parity value in the storage.

9. The non-transitory computer readable medium of claim 8, wherein the second parity value is a Q parity value.

10. The non-transitory computer readable medium of claim 7, wherein the second RAID grid location is associated with a physical location in a storage module of the set of storage modules in the storage array.

11. The non-transitory computer readable medium of claim 7, wherein the first parity value is a P parity value.

12. The non-transitory computer readable medium of claim 7, wherein the persistent storage is solid state memory.

13. A system comprising:

a persistent storage;

a processor;

a non-transitory computer readable medium comprising computer readable program code, which when executed by the processor enables the processor to;

select a first RAID grid location in a RAID grid, wherein the first RAID grid location is flagged;

select a second RAID grid location in the RAID grid;

make a first determination that the second RAID grid location is not flagged;

in response to the first determination, load first data associated with the second RAID grid location into a cache;

calculate a parity value for a corresponding set of RAID grid locations in a data grid using the first data in the cache, wherein the first RAID grid location and the second RAID grid location are in the set of RAID grid locations; and

store at least a copy of the first data and the parity value in a storage array comprising persistent storage;

wherein prior to selecting the first RAID grid location;

identify a set of storage modules that are present in the storage array;

make a second determination that at least one storage module is not present in the storage array;

in response to the second determination,

specify that the first RAID grid location is a RAID grid location that is not associated with any of the set of storage modules; and

in response to the specifying, associate the first RAID grid location with a flag.

14. The system of claim 13, further comprising computer readable program code, which when executed by the computer processor enables the computer processor to:

select a third RAID grid location in the RAID grid;

make a second determination that the third RAID grid location is flagged;

in response to the second determination, generate tracking information specifying that the third RAID grid location is flagged;

select a fourth RAID grid location in the RAID grid;

make a third determination that the fourth RAID grid location is not flagged;

in response to the third determination, load third data associated with the fourth RAID grid location into the cache;

calculate a second parity value for a corresponding second set of RAID grid locations in the data grid using the second data in the cache and the tracking information, wherein the third RAID grid location and the fourth RAID grid location are in the second set of RAID grid locations; and

store at least a copy of the second data and the second parity value in the storage.

15. The system of claim 14, wherein the second parity value is a Q parity value.

16. The system of claim 13, wherein the second RAID grid location is associated with a physical location in a storage module of the set of storage modules in the storage array.

17. The system of claim 13, wherein the first parity value is a P parity value.