RANGE BASED REBUILDER FOR USE WITH A DISPERSED DATA STORAGE NETWORK

• US 20100306578A1
• Filed: 12/29/2009
• Published: 12/02/2010
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: THORNTON, VANCE T., HENDRICKSON, DUSTIN M., MARK, ZACHARY J., VOLVOVSKI, ILYA, BELLANCA, JAMIE
• Granted Patent: US 8,352,782 B2
• Time in Patent Office: Days
• US Class Current: 714/6
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 2211/104 Metadata, i.e. metadata associated with RAID systems with parity
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

A message is generated by a computer operating on a dispersed data storage network indicating the inaccessibility of a plurality of data slices. A rebuilder application operates on the dispersed data storage grid and rebuilds inaccessible data slices, including those identified by the message.

Claims

1. A method of rebuilding data stored on a dispersed data storage network comprising a plurality of networked computers including a plurality of slice servers, each of said slice servers storing a plurality of data slices, each of said data slices being identified by a data slice identifier, whereby n of said data slices are associated with a corresponding data segment, and whereby m of said associated data slices are required to reconstruct said corresponding data segment, and further whereby m is less than n, said method comprising the steps of:

receiving a message from one of said networked computers, said message indicative of the inaccessibility of a plurality of data slices;

adding data slice identifiers identifying said plurality of data slices to a list of data slices to be rebuilt;

for each data slice identified by said list of data slices to be rebuilt;

determining a corresponding data segment;

reading at least m data slices associated with said corresponding data segment, said at least m data slices not identified on said list of data slices to be rebuilt;

reconstructing said corresponding data segment from said at least m data slices;

slicing said reconstructed corresponding data segment into n data slices, including said data slice identified by said list of data slices to be rebuilt; and

writing said data slice identified by said list of data slices to be rebuilt to one of said plurality of slice servers.

2. The method of claim 1 wherein said message specifies a range of data slice identifiers corresponding to a plurality of inaccessible data slices.

3. The method of claim 1 wherein said message specifies an inaccessible device and further comprising the step of accessing a database relating said inaccessible device to a list of data slice identifiers corresponding to said plurality of inaccessible data slices.

4. The method of claim 3 wherein said inaccessible device is one of the group consisting of a data store associated with a slice server, a slice server, and a site including a plurality of slice servers.

5. A method of rebuilding data stored on a dispersed data storage network comprising a plurality of networked computers including a plurality of slice servers, each of said slice servers storing a plurality of data slices, each of said data slices being identified by a data slice identifier and including a data portion and a first checksum, whereby n of said data slices are associated with a corresponding data segment, and whereby m of said associated data slices are required to reconstruct said corresponding data segment, and further whereby m is less than n, said method comprising the steps of:

reading a data slice stored on one of said slice servers;

computing a second checksum based on the data portion of said data slice;

comparing said second checksum with said first checksum;

adding a data slice identifier identifying said data slice to a list of data slices to be rebuilt when said first checksum does not match said second checksum;

receiving a message from one of said networked computers, said message indicative of the inaccessibility of a plurality of data slices;

adding data slice identifiers identifying said plurality of data slices to said list of data slices to be rebuilt;

for each data slice identifier on said list of data slices to be rebuilt;

determining a corresponding data segment;

reading at least m data slices associated with said corresponding data segment, said at least m data slices not identified on said list of data slices to be rebuilt;

reconstructing said corresponding data segment from said at least m data slices;

slicing said reconstructed data segment into n data slices, including said data slice identified by said list of data slices to be rebuilt; and

writing said data slice identified by said list of data slices to be rebuilt to one of said plurality of slice servers.

6. The method of claim 5 wherein said message specifies a range of data slice identifiers corresponding to a plurality of inaccessible data slices.

7. The method of claim 5 wherein said message specifies an inaccessible device and further comprising the step of accessing a database relating said inaccessible device to a list of data slice identifiers corresponding to said plurality of inaccessible data slices.

8. The method of claim 7 wherein said inaccessible device is one of the group consisting of a data store associated with a slice server, a slice server, and a site including a plurality of slice servers.

9. A dispersed data storage network comprising a plurality of networked computers including a plurality of slice servers, each of said slice servers storing a plurality of data slices, each of said data slices being identified by a data slice identifier, whereby n of said data slices are associated with a corresponding data segment, and whereby m of said associated data slices are required to reconstruct said corresponding data segment, and further whereby m is less than n, said dispersed data storage network further comprising:

a computer coupled to said plurality of networked computers, said computer running a rebuilder application, said computer adapted to receive a message from one of said networked computers, said message indicative of the inaccessibility of a plurality of data slices, and in response, said rebuilder application;

adding data slice identifiers identifying said plurality of data slices to a list of data slices to be rebuilt;

for each data slice identified by said list of data slices to be rebuilt;

determining a corresponding data segment;

reading at least m data slices associated with said corresponding data segment, said at least m data slices not identified on said list of data slices to be rebuilt;

reconstructing said corresponding data segment from said at least m data slices;

slicing said reconstructed corresponding data segment into n data slices, including said data slice identified by said list of data slices to be rebuilt; and

writing said data slice identified by said list of data slices to be rebuilt to one of said plurality of slice servers.

10. The system of claim 9 said computer running the rebuilder application is a grid access computer.

11. The system of claim 9 wherein said message specifies a range of data slice identifiers corresponding to a plurality of inaccessible data slices.

12. The system of claim 9 wherein said message specifies an inaccessible device and said rebuilder application further accessing a database relating said inaccessible device to a list of data slice identifiers corresponding to said plurality of inaccessible data slices.

13. The system of claim 12 wherein said inaccessible device is one of a group consisting of a data store associated with a slice server, a slice server, and a site including a plurality of slice servers.

15. The system of claim 13 wherein said message specifies a range of data slice identifiers corresponding to a plurality of inaccessible data slices.

16. The system of claim 13 wherein said message specifies an inaccessible device and said rebuilder application further accessing a database relating said inaccessible device to a list of data slice identifiers corresponding to said plurality of inaccessible data slices.

17. The system of claim 15 wherein said inaccessible device is one of the group consisting of a data store associated with a slice server, a slice server, and a site including a plurality of slice servers.

14. A dispersed data storage network comprising a plurality of networked computers including a plurality of slice servers, each of said slice servers storing a plurality of data slices, each of said data slices being identified by a data slice identifier and including a data portion and a first checksum, whereby n of said data slices are associated with a corresponding data segment, and whereby m of said associated data slices are required to reconstruct said corresponding data segment, and further whereby m is less than n, said dispersed data storage network further comprising:

a computer coupled to said plurality of networked computers, said computer running a rebuilder application, said rebuilder application;

reading a data slice stored on one of said plurality of slice servers;

computing a second checksum based on the data portion of said data slice;

comparing said second checksum with said first checksum;

adding a data slice identifier identifying said data slice to a list of data slices to be rebuilt when said first checksum does not match said second checksum;

said computer further adapted to receive a message from one of said networked computers, said message indicative of the inaccessibility of a plurality of data slices, and in response, said rebuilder application;

adding data slice identifiers identifying said plurality of data slices to a list of data slices to be rebuilt;

for each data slice identified by said list of data slices to be rebuilt;

determining a corresponding data segment;

reading at least m data slices associated with said corresponding data segment, said at least m data slices not identified on said list of data slices to be rebuilt;

reconstructing said corresponding data segment from said at least m data slices;

slicing said reconstructed corresponding data segment into n data slices, including said data slice identified by said list of data slices to be rebuilt; and

writing said data slice identified by said list of data slices to be rebuilt to one of said plurality of slice servers.