Storage system including capability to move a virtual storage device group without moving data

• US 20050172073A1
• Filed: 01/30/2004
• Published: 08/04/2005
• Est. Priority Date: 01/30/2004
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Voigt, Doug, Woods, Hal
• Granted Patent: US 8,006,056 B2
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 11/3442 for planning or managing the needed capacity
• CPC Class Codes: G06F 2206/1012 Load balancing
• CPC Class Codes: G06F 3/0613 in relation to throughput
• 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

A storage system comprises a plurality of storage arrays, a plurality of controllers selectively coupled to ones of the storage arrays, a network fabric coupling the plurality of controllers, and a processor. The processor is capable of moving control and/or data transfer functions related to a group of elements in the plurality of storage arrays between controllers or storage arrays by transferred management information rather than data.

Claims

1. A method of moving a virtual storage device group in a storage system from a previous location to a target location comprising:

communicating data and control information in the storage system that includes a central network fabric coupling multiple controllers that control peripheral associated storage devices; and

moving control and/or data transfer functions related to a group of elements in the storage devices between controllers or storage devices by transferring management information rather than data.

2. The method according to claim 1 further comprising:

concentrating state of the virtual storage device group to at least one storage device of the storage devices;

queuing commands directed to the virtual storage device group at a level sufficiently central to enable rerouting of the commands from the previous location to the target location;

enabling hosting of the virtual storage device group by either a controller associated with the previous location or a controller associated with the target location;

uploading state of the virtual storage device group to the controller associated with the target location; and

resuming delivery of commands to the virtual storage device group, the commands being rerouted to the target location.

3. The method according to claim 2 further comprising:

preparing for storage device group movement comprising;

inhibiting usage of cache and/or user data for operations that are not currently in progress;

flushing the cache; and

inhibiting usage of metadata for operations that are not currently in progress.

4. The method according to claim 2 wherein:

queuing commands directed to the virtual storage device group comprises queuing a subset of commands that affect metadata, including commands that directly change metadata and commands that depend on other commands that change metadata.

5. The method according to claim 2 further comprising:

subsequent to queuing the commands, waiting for commands in progress to complete; and

posting any remaining virtual storage device group state to the at least one storage device prior to enabling virtual storage device group hosting.

6. The method according to claim 2 further comprising:

on completion of state uploading, disabling hosting of the virtual storage device group by the controller associated with the previous location.

7. The method according to claim 6 further comprising:

for uploading failure before completion, arbitrarily associating the virtual storage device group with a controller.

8. The method according to claim 2 further comprising:

during enablement by either the controller associated with the previous location or the controller associated with the target location, in event of power loss or single failure, arbitrarily ordering non-failing controllers to determine which controllers access the virtual storage device group.

9. The method according to claim 2 further comprising:

during enablement by either the controller associated with the previous location or the controller associated with the target location, accessing data on the storage devices using the controller associated with the target location and controlling other aspects of disk management using the controller associated with the previous location.

10. The method according to claim 2 wherein concentrating virtual storage device group state further comprises:

eliminating virtual storage device group dependency on user data and metadata caching while retaining sufficient dependency to enable availability for data access.

11. A storage system comprising:

a plurality of storage arrays;

a plurality of controllers;

a network fabric selectively coupling the plurality of controllers to ones of the plurality of storage arrays; and

a processor capable of moving control and/or data transfer functions related to a group of elements in the plurality of storage arrays between controllers or storage arrays by transferred management information rather than data.

12. A storage system according to claim 11 wherein:

the plurality of controllers is configured as a plurality of controller pairs with a storage array having a restrictive physical association with one controller pair.

13. A storage system according to claim 11 wherein:

the plurality of storage arrays are grouped for Redundant Array of Independent Disks (RAID) style redundancy algorithms with group membership determined according to algorithms resident in a controller that is currently in control of the group.

14. A storage system according to claim 11 further comprising:

controller memory sources administered as virtual slots for placement of group related control and data.

15. A storage system according to claim 14 further comprising:

battery-backed memories included in the virtual slots; and

a process that mirrors information in the battery-backed memories from a primary controller to a secondary controller to maintain continuous data access in conditions of a controller failure event without disk group movement.

16. A storage system according to claim 14 wherein:

at least one virtual slot sufficiently large to accommodate the largest storage group is available when no storage group movement is in progress.

17. A storage system according to claim 11 wherein:

a controller'"'"'s internal bandwidth is sufficient to accommodate full utilization of all external bandwidth impinging on the controller.

18. A storage system according to claim 11 further comprising:

a network configured as multiple sets of vertically-associated controller pairs and storage shelves, the individual sets having a bandwidth adequate for accessing all storage arrays in the set, bandwidth between sets being limited.

19. A storage system according to claim 11 wherein:

all interaction with a storage element other than support of access to data or metadata contained on the storage element involves a controller in the same set as the storage element, support of access.

20. An article of manufacture comprising:

a controller usable medium having a computable readable program code embodied therein for moving a virtual storage device group in a storage system from a previous location to a target location, the computable readable program code further comprising;

a code capable of causing the controller to communicate data and control information in the storage system that includes a central network fabric coupling multiple controllers that control peripheral associated storage devices; and

a code capable of causing the controller to move control and/or data transfer functions related to a group of elements in the plurality of storage arrays between controllers or storage devices by transferred management information rather than data.

21. An article of manufacture comprising:

a controller usable medium having a computable readable program code embodied therein for moving a virtual storage device group in a storage system from a previous location to a target location, the storage system including a central network fabric coupling multiple controllers that control peripheral associated storage devices, the computable readable program code further comprising;

a code capable of causing the controller to concentrate state of the virtual storage device group to at least one storage device of the storage devices;

a code capable of causing the controller to queue commands directed to the virtual storage device group at a level sufficiently central to enable rerouting of the commands from the previous location to the target location;

a code capable of causing the controller to enable hosting of the virtual storage device group by either a controller associated with the previous location or a controller associated with the target location;

a code capable of causing the controller to upload state of the virtual storage device group to the controller associated with the target location; and

a code capable of causing the controller to resume delivery of commands to the virtual storage device group, the commands being rerouted to the target location.

22. A storage system comprising:

means for moving a virtual storage device group in a storage system from a previous location to a target location;

means for communicating data and control information in the storage system that includes a central network fabric coupling multiple controllers that control peripheral associated storage devices; and

means for moving control and/or data transfer functions related to a group of elements in the plurality of storage arrays between controllers or storage devices by transferred management information rather than data.