NON-DISRUPTIVE DISK OWNERSHIP CHANGE IN DISTRIBUTED STORAGE SYSTEMS

• US 20110231602A1
• Filed: 03/19/2010
• Published: 09/22/2011
• Est. Priority Date: 03/19/2010
• Status: Abandoned Application

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Inventors: Woods, Harold, Culter, Bradley
• Application Number:
  US12/727,998
• Publication Number:
  US 20110231602A1
• Time in Patent Office: Days
• US Class Current: 711/112
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

Non-disruptive disk ownership change in a distributed storage system is disclosed. The distributed storage system may having a first storage controller for managing a first storage pool, and a second storage controller. An exemplary method may include entering a preparation phase to transfer control of the first storage pool from the first storage controller to the second storage controller. The method may also include suspending writing normal I/O to the first storage pool and holding at the first storage controller any new I/O for the first storage pool. The method may also include rejecting the I/O requests held by the first storage controller after the second storage controller assumes ownership of the first storage pool.

Claims

1. A method for non-disruptive disk ownership change in a distributed storage system, the distributed storage system having a first storage controller for managing a first storage pool, and a second storage controller, the method comprising:

entering a preparation phase to transfer control of the first storage pool from the first storage controller to the second storage controller;

suspending writing normal I/O to the first storage pool and holding at the first storage controller any new I/O for the first storage pool; and

rejecting the I/O requests held by the first storage controller after the second storage controller assumes ownership of the first storage pool.

2. The method of claim 1, further comprising triggering the ownership transfer.

3. The method of claim 1, wherein normal I/O operations continue at the first storage controller during preparation for transferring ownership of the first storage pool to the second storage controller.

4. The method of claim 3, wherein the preparation is within a timeout period.

5. The method of claim 3, wherein the preparation is without participation by any other storage controller.

6. The method of claim 3, further comprising holding normal I/O by the first storage controller while ownership of the first storage pool is transferred to the second storage controller.

7. The method of claim 6, further comprising rejecting normal I/O held by the first storage controller after ownership of the first storage pool is transferred to the second storage controller.

8. The method of claim 7, further comprising sending information to an I/O initiator of the normal I/O held by the first storage controller, the information notifying the I/O initiator of ownership transfer of the first storage pool to the second storage controller.

9. The method of claim 8, further comprising client discovery of ownership of the first storage pool by the second storage controller after ownership transfer of the first storage pool to the second storage controller.

10. A distributed storage system comprising:

a first storage controller for managing a first storage pool, and a second storage controller;

an online operation initiated by the first storage controller to provide a disk ownership change, the online operation executable in response to a transfer request to;

suspend writing normal I/O to the first storage pool and holding at the first storage controller any new I/O for the first storage pool; and

reject the I/O requests held by the first storage controller after the second storage controller assumes ownership of the first storage pool.

11. The system of claim 10, wherein the first storage controller is part of a first controller pair.

12. The system of claim 10, wherein the second storage controller is part of a second controller pair.

13. The system of claim 10, wherein the transfer request is initiated manually in response to a trigger.

14. The system of claim 10, wherein the transfer request is initiated automatically in response to a trigger.

15. The system of claim 10, further comprising a trigger to initiate the transfer request, the trigger including at least one of the following:

load balancing, failure of a controller, expansion of the storage system, and moving an application from one server to another server.

16. A first storage controller for managing a first storage pool, comprising:

program code including an executable process, the executable process initiated by the first storage controller to provide a non-disruptive disk ownership change, the process being executable to;

send a request to initiate a transfer of ownership of the first storage pool from the first storage controller to a second storage controller;

enter a preparation phase to transfer control of the first storage pool from the first storage controller to the second storage controller;

suspend writing normal I/O to the first storage pool and holding at the first storage controller any new I/O for the first storage pool;

assume ownership of the first storage pool by the second storage controller; and

reject the I/O requests held by the first storage controller.

17. The first storage controller of claim 16, wherein the first storage controller is part of a first controller pair.

18. The first storage controller of claim 16, wherein the second storage controller is part of a second controller pair.

19. The first storage controller of claim 16, wherein the second storage controller manages a second storage pool.

20. The first storage controller of claim 19, wherein the trigger includes at least one of the following:

load balancing, failure of a controller, expansion of the storage system, and moving an application from one server to another server.