DATA ACCESS METHOD, DEVICE AND COMPUTER PROGRAM PRODUCT

• US 20200133508A1
• Filed: 10/04/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Original Assignee: Emc IP Holding Company LLC (Dell Technologies Inc.)
• Inventors: Feng, Changyu, Liu, Yousheng, Tang, Haiying, Zhang, Xiaobo, Xia, Sihang
• Granted Patent: US 11,461,012 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

Data access techniques involve: determining whether there is a copy operation that is being performed from a first LU to a second LU in response to receiving a write operation request for a first data block in the first logic unit (LU); detecting a copy status of data in the first data block in response to determining that there is the copy operation that is being performed; and determining a processing strategy of the write operation request during execution of the copy operation based on the copy status.

Claims

1. A data access method, comprising:

in response to receiving a request of a write operation for a first data block in a first logic unit (LU), determining whether a copy operation that is being performed from the first LU to a second LU exists;

in response to determining that the copy operation that is being performed exists, detecting a copy status of data in the first data block; and

determining, based on the copy status, a processing strategy of the request of the write operation during the copy operation.

2. The method according to claim 1, wherein the determining a processing strategy of the request of the write operation comprises:

in response to the copy status indicating that the data in the first data block is not copied, performing the write operation for the first data block.

3. The method according to claim 1, wherein the determining a processing strategy of the request of the write operation comprises:

in response to the copy status indicating that data in the first data block is being copied, delaying the write operation for the first data block.

4. The method according to claim 3, further comprising:

in response to detecting that the copy status becomes a status indicating that data in the first data block is already copied, performing the write operation for the data in the first data block.

5. The method according to claim 1, wherein the determining a processing strategy of the request of the write operation comprises:

in response to the copy status indicating that data in the first data block is already copied,

performing a write operation for data in the first data block; and

performing a write operation for data that is in the second LU and in a second data block corresponding to the first data block, wherein the data in the second data block is a copy of the data in the first data block.

6. The method according to claim 1, further comprising:

prior to the beginning of the copy operation,

creating a first set of access paths from a host to a first set of disks;

creating a mapping relationship between the first LU and the second LU; and

creating a second set of access paths from the host to a second set of disks.

7. The method according to claim 6, further comprising:

after a completion of the copy operation,

in response to receiving a further request of a write operation for the first data block, switching a path for data access from an access path in a first set of access paths to an access path in a second set of access paths, so that a response to the further request is made with the second LU.

8. The method according to claim 1, further comprising:

performing the copy operation, wherein performing the copy operation comprises;

in response to detecting that the data in the first data block is zero, skipping a copy operation for the data in the first data block.

9. A data access device, comprising:

a processing unit; and

a memory coupled to the processing unit and storing instructions that, when executed by the processing unit, perform the following acts;

in response to receiving a request of a write operation for a first data block in a first logic unit (LU), determining whether a copy operation that is being performed from a first LU to a second LU exists;

in response to determining that the copy operation that is being performed exists, detecting a copy status of data in the first data block; and

determining, based on the copy status, a processing strategy of the request of the write operation during execution of the copy operation.

10. The device according to claim 9, wherein the determining a processing strategy of the request of the write operation comprises:

performing the write operation for the first data block in response to the copy status indicating that data in the first data block is not copied.

11. The device according to claim 9, wherein the determining a processing strategy of the request of the write operation comprises:

in response to the copy status indicating that data in the first data block is being copied, delaying the write operation for the first data block.

12. The device according to claim 11, wherein the acts further comprise:

in response to detecting that the copy status becomes a status indicating that data in the first data block is already copied, performing the write operation for the data in the first data block.

13. The device according to claim 9, wherein the determining a processing strategy of the request of the write operation comprises:

in response to the copy status indicating that data in the first data block is already copied,

performing a write operation for data in the first data block; and

performing a write operation for data that is in the second LU and in a second data block corresponding to the first data block, wherein the data in the second data block is a copy of the data in the first data block.

14. The device according to claim 9, wherein the acts further comprise:

prior to the beginning of the copy operation,

creating a first set of access paths from a host to a first set of disks;

creating a mapping relationship between the first LU and the second LU; and

creating a second set of access paths from the host to a second set of disks.

15. The device according to claim 14, wherein the acts further comprise:

after a completion of the copy operation,

in response to receiving a further request of a write operation for the first data block, switching a path for data access from an access path in a first set of access paths to an access path in a second set of access paths, so that a response to the further request is made with the second LU.

16. The device according to claim 9, wherein the acts further comprise:

performing the copy operation, wherein performing the copy operation comprises;

in response to detecting that the data in the first data block is zero, skipping a copy operation for the data in the first data block.

17. A computer program product having a non-transitory computer readable medium which stores a set of instructions to perform data access;

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

in response to receiving a request of a write operation for a first data block in a first logic unit (LU), determining whether a copy operation that is being performed from the first LU to a second LU exists;

in response to determining that the copy operation that is being performed exists, detecting a copy status of data in the first data block; and

determining, based on the copy status, a processing strategy of the request of the write operation during the copy operation.