Methods and apparatus for minimally disruptive data migration

Patent metadata

Field	Value
Publication number	US-9417812-B1
Application number	US-96436407-A
Country	US
Kind code	B1
Filing date	Dec 26, 2007
Priority date	Dec 26, 2007
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

Methods and apparatus for migrating data with minimal disruption in a storage virtualization system. In one embodiment, a method includes collecting information on a backend logical unit (LUN) having a direct path from a host, presenting the backend LUN to the host through a virtual target via the storage virtualization application, disconnecting the direct path from the host to the backend LUN so that the backend LUN is accessed by the host via the storage virtualization application transparently to the host, and migrating data from the backend LUN to a destination storage transparently to the host.

First claim

What is claimed is:

1. A method, comprising: migrating data in a storage virtualization environment from a backend LUN to a destination storage using a data migration module stored in a device coupled to a host by a switch fabric, using the data migration module comprising:
collecting information on a personality of the backend LUN by collecting responses from the backend LUN to Small Computer System Interface (SCSI) commands issued from the host to the backend LUN while the host is coupled to the backend LUN by the switch fabric in a direct path;
presenting a virtualization of the backend LUN to include the personality of the backend LUN to the host, using the collected information, through a virtual target at the device using a first path through the switch while the host is coupled to the backend LUN by the switch fabric in the direct path;
disconnecting the host from the direct path to the backend LUN while a destination storage is coupled to the device by the switch fabric; and
migrating data from the backend LUN to the destination storage transparently to the host after disconnecting the host from the direct path to the backend LUN.

2. The method of claim 1 , wherein the backend LUN is identified with the same unique ID for both the direct path to the host and the virtual target.

3. The method of claim 1 , wherein collecting information includes static information collection.

4. The method of claim 1 , wherein collecting information includes information collection through monitoring.

5. The method of claim 1 , wherein collecting information includes self-learning the personality of the backend LUN.

6. The method of claim 1 , further comprising persistently storing the collected information on the backend LUN.

7. The method of claim 6 , further comprising utilizing, after the backend LUN is disconnected, the collected information on the backend LUN to present to the host a personality identical to that of the backend LUN and writing data to the destination storage.

8. The method of claim 1 , further comprising collecting the information on the backend logical unit (LUN) by a virtual initiator.

9. The method of claim 1 , further comprising removing the backend LUN after completion of the data migration to the destination storage.

10. The method of claim 1 , further comprising moving the destination storage to a remote location.

11. The method of claim 1 , further comprising, during the data migration, mirroring writes to the backend LUN and the destination storage and servicing reads only through the backend LUN.

12. The method of claim 1 , further comprising retaining a personality of the backend LUN until cleared by a user.

13. An article, comprising:
a non-transitory machine-readable medium that stores executable instructions to migrate data in a storage virtualization environment from a backend logical unit (LUN) to a destination storage, a host being coupled to a device comprising the non-transitory machine-readable medium using a switch fabric, the backend LUN being coupled to the host using the switch fabric to form a direct path, a destination storage being coupled to the device using the switch fabric, the instructions causing a machine to:
collect information on a personality of the backend LUN by collecting responses to Small Computer System Interface (SCSI) commands issued from the host to the backend LUN while the host is coupled to the backend LUN by the switch fabric in the direct path;
present a virtualization of the backend LUN to include the personality of the backend LUN to the host, using the collected information, through a virtual target at the device using a first path through the switch fabric while the host is coupled to the backend LUN by the switch fabric in the direct path;
disconnect the host from the direct path to the backend LUN while a destination storage is coupled to the device by the switch fabric;
migrate data from the backend LUN to the destination storage transparently to the host after disconnecting the host from the direct path.

14. The article according to claim 13 , wherein the backend LUN is identified with the same unique ID for both the direct path to the host and the virtual target.

15. The article according to claim 13 wherein the instructions causing the machine to collect information comprises instructions causing the machine to self-learn.

16. The article according to claim 13 , further comprising instructions causing the machine to:
persistently store the collected information on the backend LUN, and
utilize, after the backend LUN is disconnected, the collected information on the backend LUN to present to the host a personality identical to that of the prior storage and writing data to the destination storage.

17. The article according to claim 13 , further comprising instructions causing the machine to collect the information on the backend logical unit (LUN) by a virtual initiator.

18. A system, comprising:
a host coupled to a device comprising a data migration module in a storage virtualization environment using a switch fabric;
a backend logical unit (LUN) coupled to the host using the switch fabric to form a direct path, the backend LUN being coupled to the device using the switch fabric;
a destination storage coupled to the device using the switch fabric; and
wherein the data migration module is configured to:
collect information on a personality of the backend LUN by collecting responses from the backend LUN to Small Computer System Interface (SCSI) commands issued from the host to the backend LUN while the host is coupled to the backend LUN by the switch fabric in the direct path;
present a virtualization of the backend LUN to include the personality of the backend LUN to the host, using the collected information, through a virtual target at the device using a first path though the switch fabric while the host is coupled to the backend LUN by the switch fabric in the direct path;
disconnect the host from the direct path to the backend LUN while a destination storage is coupled to the device by the switch fabric; and
migrate data from the backend LUN to the destination storage transparently to the host after disconnecting the host from the direct path.

19. The system according to claim 18 , wherein the backend LUN is identified with the same unique ID for both the direct path to the host and the virtual target.

20. The system according to claim 18 , wherein the collected information on the backend LUN is stored persistently to enable utilization, after the backend LUN is disconnected, of the collected information on the backend LUN to present to the host a personality identical to that of the prior storage and writing data to the destination storage.

Assignees

• Palekar Ashish Arun
• Swayampakulaa Sudhindra
• Chinthapatla Karunaker
• Waxman Matthew D
• Emc Corp

Inventors

• Palekar Ashish Arun
• Swayampakulaa Sudhindra
• Chinthapatla Karunaker
• Waxman Matthew D

Classifications

• G06F3/0683

  Plurality of storage devices · CPC title

• G06F3/0607

  by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device · CPC title

• G06F3/0647 Primary

  Migration mechanisms · CPC title

• G06F3/0617

  in relation to availability · CPC title

• G06F3/067

  Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS] · CPC title