System and method for restriping data across a plurality of volumes

• US 20060248379A1
• Filed: 04/29/2005
• Published: 11/02/2006
• Est. Priority Date: 04/29/2005
• Status: Active Grant

• Current Assignee: NetApp, Inc.
• Original Assignee: NetApp, Inc.
• Inventors: Jernigan, Richard P. IV
• Granted Patent: US 7,904,649 B2
• Time in Patent Office: Days
• US Class Current: 714/6
• CPC Class Codes: G06F 11/1096 Parity calculation or recalculation after configuration or reconfiguration of the system
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0632 by initialisation or re-initialisation of storage systems
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD

Abstract

A system and method re-stripes one or more data containers across a striped volume set (SVS) that has been modified by the addition of one or more volumes. The SVS is associated with an existing set of striping rules that define a stripe algorithm, a stripe width and an ordered list of volumes distributed across a plurality of nodes interconnected as a cluster. Each node of the cluster includes (i) a disk element (D-blade) adapted to service a volume of the SVS and (ii) a network element (N-blade) adapted to redirect a data access request to any D-blade of the cluster. Notably, the content of each data container is apportioned among the volumes of the SVS to thereby improve the efficiency of storage service provided by the cluster. To that end, the stripe algorithm specifies the manner in which the data container content is apportioned as stripes across the plurality of volumes, while the stripe width specifies the size/width of each stripe.

Claims

5-1. The system of claim 5 further comprising:

means for determining, for each stripe in the striped volume set, if the stripe is located on a correct volume; and

means for relocating, in response to determining that the stripe is not located on the correct volume, the stripe to the correct volume.

8. A computer readable medium for restriping data across a striped volume set, the computer readable medium including program instructions for performing the steps of:

creating a new striping rule set identifying a set of volumes to be utilized as the striped volume set;

in response to receiving an operation directed to a stripe of the data, determining if the stripe is located on a correct volume of the set of volumes; and

in response to determining that the stripe is not located on the correct volume, relocating the stripe to the correct volume before processing the received operation.

9. A system for restriping data across a striped volume set, the system comprising:

a plurality of computers, each of the plurality of computers comprising a container striping module, each container striping module adapted to determine, for each stripe in the striped volume set, if the stripe is currently located on a correct volume and, in response to determining that the stripe is not on a correct volume, relocating the stripe to the correct volume.

10. The system of claim 9 wherein the determination of whether the stripe is on the correct volume is made by a locate function that analyzes an inode, an offset and a set of striping rules.

11. The system of claim 10 wherein the set of striping rules comprises an ordered list of volumes.

12. A method for restriping data across a striped volume set, the method comprising the steps of:

receiving a command directed to a file in the striped volume set;

determining which of a plurality of volumes of the striped volume set stores a stripe associated with the received command, the determination being made by selecting one of a plurality of striping rules associated with the striped volume set; and

forwarding the received command to a computer serving the volume storing the stripe associated with the command.

13. The method of claim 12 wherein the step of selecting one of a plurality of file striping rules associated with the striped volume set comprises the step of analyzing a striped volume set identifier in a file handle associated with the received command.

14. The method of claim 12 wherein the step of selecting one of a plurality of striping rules associated with the striped volume set comprises the step of analyzing an inode generation value associated with an inode associated with a data container being operated on by the received command.

15. The method of claim 14 wherein each of the plurality of striping rules comprises a generation value floor that identifies which inodes are associated each of the plurality of striping rules.

17. The system of claim 15 wherein the means for selecting one of a plurality of striping rules associated with the striped volume set comprises means for analyzing a striped volume set identifier in a file handle associated with the received command.

18. The method of claim 15 wherein the means for selecting one of a plurality of striping rules associated with the striped volume set comprises means for analyzing an inode generation value associated with an inode associated with a data container being operated on by the received command.

16. A system for restriping data across a striped volume set, the system comprising:

means for receiving a command directed to a file in the striped volume set;

means for determining which of a plurality of volumes of the striped volume set stores a stripe associated with the received command, the determination being made by selecting one of a plurality of striping rules associated with the striped volume set; and

means for forwarding the received command to a computer serving the volume storing the stripe associated with the command.

19. A computer readable medium for restriping data across a striped volume set, the computer readable medium including program instructions for performing the steps of:

receiving a command directed to a file in the striped volume set;

determining which of a plurality of volumes of the striped volume set stores a stripe associated with the received command, the determination being made by selecting one of a plurality of striping rules associated with the striped volume set; and

forwarding the received command to a computer serving the volume storing the stripe associated with the command.

20. A system for restriping data across a striped volume set, the system comprising:

one or more storage servers having a container striping module adapted to process commands directed to the striped volume set; and

at least one multi-protocol engine having a cluster fabric interface module adapted to determine which of a plurality of striping rules to utilize in processing a received command, the cluster fabric interface module further adapted to forward the received command to one of the one or more storage servers for processing in response to determining which of the plurality of striping rules to utilize.