SEAMLESS DATA MIGRATION IN A CLUSTERED ENVIRONMENT

• US 20180157429A1
• Filed: 12/06/2016
• Published: 06/07/2018
• Est. Priority Date: 12/06/2016
• Status: Active Grant

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Dell Products LP (Dell Technologies Inc.)
• Inventors: VENKAT, Prakash, AMBAT, Gopakumar, KONING, G. Paul, THOMAS, Ryan J., BILUGU, Raghuram, OELKE, Daniel R.
• Granted Patent: US 10,353,640 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0647 Migration mechanisms
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A data management method and system for migrating a data volume from a source array to a destination array includes receiving an indication of a source volume to migrate from the source array to the destination array wherein the source volume comprises a clustered volume associated with a plurality of cluster hosts. A path-flip is performed by the host multipath module, to switch the paths between source and destination array. This switch is done in a seamless manner, without disrupting host I/O. The path-flip includes transferring associated metadata from source to destination and can be performed even in clustered and/or multi-host environments. Sanity timers are built-in to ensure that the path-flip completes within a stipulated time-frame and, if not, the path-flip process is aborted and I/O is resumed without any disruption.

Claims

1. A data management method for migrating a data volume from a source array to a destination array, the method comprising:

responsive to receiving an indication of a source volume to migrate from the source array to the destination array, wherein the source volume comprises a clustered volume associated with a plurality of cluster hosts, initiating a migration process, comprising;

initiating a path-flip process comprising;

instructing each cluster host to suspend input/output (I/O) operations;

responsive to detecting an exception before each of the cluster hosts successfully suspends I/O operations, instructing each cluster host to release I/O, and terminating the migration process;

disabling the source volume;

responsive to detecting an exception before the source volume is disabled successfully, sending a volume enable to the source array, instructing each cluster host to release I/O, and terminating the migration process;

instructing each of the cluster hosts to perform registration copy operations to apply source volume host registrations to the destination volume;

responsive to detecting an exception before the registration copy operations completes successfully, sending a volume enable to the source volume, instructing each cluster host to release I/O, and terminating the migration process;

sending a volume enable to the destination volume; and

responsive to detecting a destination volume status of enabled from each of the plurality of hosts, copying the source volume to the destination volume.

2. The method of claim 1, wherein detecting an exception comprises detecting at least one of:

a timeout event, a command failure, and a migration cancellation request.

3. The method of claim 2, further comprising, initiating a path-flip timer before instructing each of the cluster hosts to suspend I/O, wherein detecting a timeout event includes detecting the path-flip timer exceeding a threshold value before completing the path-flip process.

4. The method of claim 2, further comprising, initiating an abort timer after instructing each of the cluster hosts to suspend I/O, wherein detecting a timeout event includes detecting the abort timer exceeding a threshold value before completing the path-flip process.

5. The method of claim 1, further comprising, responsive to detecting a cancel request during said copying, performing a reverse path-flip comprising the path-flip process with the source volume serving as the destination volume and vice versa.

6. The method of claim 5, responsive to a time out or failure during the reverse path-flip process, terminating the reverse path-flip process and resuming the copying.

7. The method of claim 1, wherein instructing each of the cluster hosts to suspend I/O includes instructing at least one cluster host to execute a vendor-specific host register command.

8. The method of claim 1, wherein configuring each cluster host to suspend I/O includes issuing hold I/O instructions to each cluster host.

9. The method of claim 1, wherein disabling the source volume includes sending a small computer system interface (SCSI) disable command.

10. The method of claim 1, wherein disabling the source volume includes sending a vendor-specific in-migration command from each cluster host to the source volume.

11. The method of claim 1, wherein the source array is of a different type of storage array than the destination array.

12. The method of claim 11, wherein an operating system of the source array differs from an operating system of the destination array.

13. The method of claim 11, wherein the source array maintains a one-to-one correspondence between iSCSI targets and logical unit numbers (LUNs) and wherein the destination array supports a one-to-many relationship between iSCSI targets and storage volumes.

14. The method of claim 1, further comprising:

creating a proxy volume on the destination array;

connecting the proxy volume to the source volume;

mapping the proxy volume to the cluster host; and

requesting at least one of the cluster hosts to build a passive path to the proxy volume.

15. An information handling system comprising:

a processor; and

a computer readable storage medium including stored instructions that, when executed by the processor, cause the processor to perform operations comprising;

responsive to receiving an indication of a source volume to migrate from a source array to a destination array, wherein the source volume comprises a clustered volume associated with a plurality of cluster hosts, initiating a path-flip process comprising;

configuring each cluster host to suspend input/output (I/O) operations;

responsive to detecting an exception before each cluster host suspends I/O successfully, instructing each cluster host to release I/O, and terminating the migration process;

disabling the source volume;

responsive to detecting an exception before the volume disable completes, sending a volume enable to the source array, instructing each cluster host to release I/O and terminating the migration process;

instructing each of the cluster hosts to perform registration copy operations to apply source volume host registrations to the destination volume;

responsive to detecting an exception before the registration copy operations complete, sending a volume enable to the source volume, instructing each cluster host to release I/O, and terminating the migration process;

sending a volume enable to the destination volume; and

responsive to detecting a destination volume status of enabled from each of the plurality of hosts, copying the source volume to the destination volume;

wherein the source array maintains a one-to-one correspondence between targets and logical unit numbers (LUNs) and wherein the destination array supports a one-to-many relationship between small computer system interface over Internet (iSCSI) targets and storage volumes.

16. The information handling system of claim 15, wherein the operations include:

initiating a path-flip timer before instructing each of the cluster hosts to execute the hold I/O command, wherein detecting a timeout event includes detecting the path-flip timer exceeding a threshold value before completing the path-flip process;

initiating an abort timer after instruction each host to stop sending I/O to storage, wherein detecting the timeout event includes detecting the abort timer exceeding a threshold value before completing the path-flip process;

responsive to a cancel request during said copying, performing a reverse path-flip comprising the flip-path process with the source volume serving as the destination volume and vice versa;

responsive to a time out or failure during the reverse path-flip, terminating the reverse path-flip and resuming the copying.

17. The information handling system of claim 16, wherein configuring each cluster host to suspend I/O includes instructing at least one cluster host to execute a vendor-specific host migration register command.

18. A non-transitory computer readable medium including processor-executable instructions that, when executed by the processor, cause the processor to perform operations comprising:

responsive to receiving an indication of a source volume to migrate from a source array to a destination array wherein the source volume comprises a clustered volume associated with a plurality of cluster hosts, initiating a path-flip process comprising;

configuring each cluster host to suspend input/output (I/O) operations;

responsive to detecting an exception before each cluster host suspends I/O successfully, instructing each cluster host to release I/O, and terminating the migration process;

disabling the source volume;

responsive to detecting an exception before the volume disable completes, sending a volume enable to the source array, instructing each cluster host to release I/O and terminating the migration process;

instructing each of the cluster hosts to perform registration copy operations to apply source volume host registrations to the destination volume;

responsive to detecting an exception before the registration copy operations complete, sending a volume enable to the source volume, instructing each cluster host to release I/O, and terminating the migration process;

sending a volume enable to the destination volume; and

responsive to detecting a destination volume status of enabled from each of a plurality of cluster hosts, copying the source volume to the destination volume.

19. The computer readable medium of claim 18, wherein the operations include:

initiating a path-flip timer before instructing each of the cluster hosts to execute the suspend I/O command, wherein detecting a timeout event includes detecting the path-flip timer exceeding a threshold value before completing the path-flip process;

initiating an abort timer after instructing each host to stop sending I/O to storage, wherein detecting the timeout event includes detecting the abort timer exceeding a threshold value before completing the path-flip process;

responsive to a cancel request during said copying, performing a reverse path-flip comprising the flip-path process with the source volume serving as the destination volume and vice versa;

responsive to a time out or failure during the reverse path-flip, terminate the reverse path-flip and resuming the copying.

20. The computer readable medium of claim 19, wherein configuring each host to suspend I/O includes instructing at least one host to execute a vendor-specific host migration register command.