Disk replacement via hot swapping with variable parity

• US 20020174296A1
• Filed: 01/29/2002
• Published: 11/21/2002
• Est. Priority Date: 01/29/2001
• Status: Abandoned Application

• Current Assignee: Braodband Storage LLC, Snap Appliance, Inc. (Silicon Valley Technology Partners LLC)
• Original Assignee: Adaptec Incorporated (Steel Partners Holdings LP)
• Inventors: Schweitzer, James R., Bolstad, Gregory D., Staub, John R., Randall, Jay G., Priester, Wilbur George, Ulrich, Thomas R.
• Application Number:
  US10/060,939
• Publication Number:
  US 20020174296A1
• Time in Patent Office: Days
• US Class Current: 711/114
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 11/2035 without idle spare hardware
• CPC Class Codes: G06F 11/2048 where the redundant components share neither address space nor persistent storage
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 2201/84 Using snapshots, i.e. a logical point-in-time copy of the data
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system

Abstract

A system and method for enhanced disk replacement via hot swapping with variable parity is described. The system and method operate on a computer storage system that includes a plurality of disk drives for storing distributed parity groups. Each distributed parity group includes storage blocks. The storage blocks include one or more data blocks and a parity block that is associated with the one or more data blocks. Each of the storage blocks is stored on a separate disk drive such that no two storage blocks from a given parity set reside on the same disk drive. The computer storage system further includes file system metadata to describe a location of each of the storage blocks. The computer storage system further includes a resource-allocation module to recognize a new disk drive that is hot-swapped into the plurality of disk drives during file system operation and to use the new disk drive to store one or more storage blocks.

Claims

1. A computer storage system, comprising:

a plurality of disk drives for storing distributed parity groups, each distributed parity group comprising storage blocks, said storage blocks comprising one or more data blocks and a parity block associated with said one or more data blocks, each of said storage blocks stored on a separate disk drive such that no two storage blocks from a given parity group reside on the same disk drive;

file system metadata to describe a location of each of said storage blocks;

a resource-allocation module to recognize a new disk drive hot-swapped into said plurality of disk drives during file system operation and to use said new disk drive to store one or more storage blocks.

2. The computer storage system of claim 1, wherein a size of a first distributed parity group is larger than a size of a second distributed parity group within a first file.

3. The computer storage system of claim 1, further comprising metadata to specify which disk drive in said plurality of disk drives and said new disk drive contains each storage block.

4. The computer storage system of claim 1, wherein said new disk drive is provided to a Fibre Channel network.

5. The computer storage system of claim 1, wherein a file is organized as one or more of said distributed parity groups.

6. The computer storage system of claim 1, wherein said file system metadata comprises information to specify a logical block address for each storage block in a distributed parity group.

7. The computer storage file system of claim 1, wherein an extent of a first distributed parity group of a file is larger than an extent of a second distributed parity group of said file.

8. The computer storage file system of claim 23, further comprising a load-balancing module to distribute one or more existing storage blocks to said new disk drive.

9. A method for hot-swapping a new storage device in a storage system, comprising:

recognizing said new storage device;

adding said new disk drive to a list of previously-available storage devices to produce a list of currently-available storage devices;

determining a size of a new parity group, said size describing a number of data blocks in said new parity group;

computing a parity block for said parity group; and

storing one of said data blocks or said parity block on said new storage device.

10. The method of claim 9, further comprising storing metadata to describe a disk and logical block location of each of said data blocks and said parity block.

11. The method of claim 9, further comprising combining a first parity group having a first size and a second parity group having a second size to produce a combined parity group having a third size, wherein said third size specifies a number of data blocks that is one less than the number of currently-available storage devices.

12. The method of claim 9, wherein said new storage device comprises a disk drive.

13. The method of claim 9, further comprising:

recognizing that a selected storage device has gone offline, removing said selected storage device from said list of currently-available storage devices to produce a list of remaining storage devices;

reconstructing data stored on said selected storage device;

storing said reconstructed data on one or more of said remaining storage devices; and

updating file system metadata to facilitate locating said reconstructed data.