METHOD, DEVICE, AND COMPUTER READABLE STORAGE MEDIUM FOR MANAGING REDUNDANT ARRAY OF INDEPENDENT DISKS

• US 20200133775A1
• Filed: 09/24/2019
• Published: 04/30/2020
• Est. Priority Date: 10/25/2018
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Kang, Jianbin, Gao, Jian, Han, Geng
• Granted Patent: US 11,579,975 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1084 Degraded mode, e.g. caused by single or multiple storage removals or disk failures
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 2201/81 Threshold
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0634 by changing the state or mode of one or more devices
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Techniques manage a redundant array of independent disks. In such a technique, a response time of a first storage device in the RAID is compared to a first threshold. In response to the response time of the first storage device exceeding the first threshold, the first storage device is configured as a pseudo-degraded storage device, such that the pseudo-degraded storage device is responsive to write requests only.

Claims

1. A method of managing a Redundant Array of Independent Disks (RAID), comprising:

comparing a response time of a first storage device in the RAID to a first threshold; and

in response to the response time of the first storage device exceeding the first threshold, configuring the first storage device as a pseudo-degraded storage device, such that the pseudo-degraded storage device is responsive to write requests only.

2. The method of claim 1, wherein configuring the first storage device as the pseudo-degraded storage device comprises:

in response to receiving a read request for reading first data from the pseudo-degraded storage device, reading the first data from a second storage device of the RAID; and

in response to receiving a write request for writing second data to the pseudo-degraded storage device, writing the second data to the pseudo-degraded storage device.

3. The method of claim 1, wherein the first storage device is a storage device in the RAID with the longest response time.

4. The method of claim 2, wherein writing the second data to the pseudo-degraded storage device comprises:

reading, from the second storage device of the RAID, data associated with the write request to calculate parity data; and

writing the parity data to a parity storage device in the RAID.

5. The method of claim 1, further comprising:

in response to the response time of the pseudo-degraded storage device decreasing below a second threshold for a predetermined period of time, configuring the pseudo-degraded storage device as a normal storage device, the second threshold being less than the first threshold.

6. The method of claim 1, further comprising:

in response to the response time of the pseudo-degraded storage device exceeding a third threshold, ignoring a write request for an extent in the pseudo-degraded storage device with a highest write load, the third threshold being greater than the first threshold.

7. The method of claim 6, further comprising:

adding the extent into a list of degraded extents of the pseudo-degraded storage device; and

in response to the number of degraded extents in the list of degraded extents exceeding a predetermined threshold, migrating extents in the pseudo-degraded storage device to a third storage device in the RAID.

8. The method of claim 6, further comprising:

in response to a response time of the extent decreasing below a fourth threshold within a predetermined period of time, performing a data rebuild operation on the extent, the fourth threshold being less than the first threshold.

9. The method of claim 8, further comprising:

in response to the response time of the extent failing to decrease to the fourth threshold within the predetermined period of time, migrating the extent to a spare extent in a fourth storage device in the RAID.

10. A device for managing a Redundant Array of Independent Disks (RAID), comprising:

a processing unit;

a memory coupled to the processing unit and comprising instructions stored thereon, the instructions, when executed by the processing unit, causing the device to perform acts comprising;

comparing a response time of a first storage device in the RAID to a first threshold; and

in response to the response time of the first storage device exceeding the first threshold, configuring the first storage device as a pseudo-degraded storage device, such that the pseudo-degraded storage device is responsive to write requests only.

11. The device of claim 10, wherein configuring the first storage device as the pseudo-degraded storage device comprises:

in response to receiving a read request for reading first data from the pseudo-degraded storage device, reading the first data from a second storage device of the RAID; and

in response to receiving a write request for writing second data to the pseudo-degraded storage device, writing the second data to the pseudo-degraded storage device.

12. The device of claim 10, wherein the first storage device is a storage device in the RAID with the longest response time.

13. The device of claim 11, wherein writing the second data to the pseudo-degraded storage device comprises:

reading, from the second storage device of the RAID, data associated with the write request to calculate parity data; and

writing the parity data to a parity storage device in the RAID.

14. The device of claim 10, wherein the acts further comprise:

in response to the response time of the pseudo-degraded storage device decreasing below a second threshold for a predetermined period of time, configuring the pseudo-degraded storage device as a normal storage device, the second threshold being less than the first threshold.

15. The device of claim 10, wherein the acts further comprise:

in response to the response time of the pseudo-degraded storage device exceeding a third threshold, ignoring a write request for an extent in the pseudo-degraded storage device with a highest write load, the third threshold being greater than the first threshold.

16. The device of claim 15, wherein the acts further comprise:

adding the extent into a list of degraded extents of the pseudo-degraded storage device; and

in response to the number of degraded extents in the list of degraded extents exceeding a predetermined threshold, migrating extents in the pseudo-degraded storage device to a third storage device in the RAID.

17. The device of claim 15, wherein the acts further comprise:

in response to a response time of the extent decreasing below a fourth threshold within a predetermined period of time, performing a data rebuild operation on the extent, the fourth threshold being less than the first threshold.

18. The device of claim 17, wherein the acts further comprise:

in response to the response time of the extent failing to decrease to the fourth threshold within the predetermined period of time, migrating the extent to a spare extent in a fourth storage device in the RAID.

19. A computer program product having a non-transitory computer readable medium which stores a set of instructions to manage a Redundant Array of Independent Disks (RAID);

the set of instructions, when carried out by computerized circuitry, causing the computerized circuitry to perform a method of;

comparing a response time of a first storage device in the RAID to a first threshold; and

in response to the response time of the first storage device exceeding the first threshold, configuring the first storage device as a pseudo-degraded storage device, such that the pseudo-degraded storage device is responsive to write requests only.