Adjusting data dispersal in a dispersed storage network

• US 8,495,466 B2
• Filed: 12/31/2010
• Issued: 07/23/2013
• Est. Priority Date: 03/16/2010
• Status: Expired due to Fees

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Cilfone, Bart, Resch, Jason K., Gladwin, S. Christopher
• Primary Examiner(s): Ehne, Charles
• Application Number:
  US12/983,214
• Publication Number:
  US 20110231733A1
• Time in Patent Office: 935 Days
• Field of Search: 714/47.1, 714/763
• US Class Current: 714/763
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: H03M 13/35 Unequal or adaptive error protection, e.g. by providing a different level of protection according to significance of source information or by adapting the coding according to the change of transmission channel characteristics
• CPC Class Codes: H03M 13/356 Unequal error protection [UEP]
• CPC Class Codes: H04N 21/2181 comprising remotely distributed storage units, e.g. when movies are replicated over a plurality of video servers distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097

Abstract

A method begins by a processing module determining a performance based indication regarding storage of a data segment as a set of encoded data slices and comparing the performance based indication with a performance threshold. When the performance based indication compares unfavorably with the performance threshold, the method continues with the processing module decoding the set of encoded data slices to reproduce the data segment, adjusting error coding dispersal storage function parameters based on the unfavorable comparison of the performance based indication with the performance threshold to produce performance adjusted error coding dispersal storage function parameters, encoding the reproduced data segment in accordance with the performance adjusted error coding dispersal storage function parameters to produce a second set of encoded data slices, and selecting a storage set of encoded data slices from the set of encoded data slices and the second set of encoded data slices.

Claims

1. A method comprises:

determining a performance based indication regarding storage of a data segment as a set of encoded data slices;

comparing the performance based indication with a performance threshold; and

when the performance based indication compares unfavorably with the performance threshold;

decoding the set of encoded data slices in accordance with error coding dispersal storage function parameters to reproduce the data segment;

adjusting the error coding dispersal storage function parameters based on the unfavorable comparison of the performance based indication with the performance threshold to produce performance adjusted error coding dispersal storage function parameters;

encoding the reproduced data segment in accordance with the performance adjusted error coding dispersal storage function parameters to produce a second set of encoded data slices; and

selecting a storage set of encoded data slices from the set of encoded data slices and the second set of encoded data slices based on a difference between the performance adjusted error coding dispersal storage function parameters and the error coding dispersal storage function parameters.

2. The method of claim 1 further comprises:

updating a storage location table to associate a corresponding slice name of a set of slice names with a corresponding encoded data slice of the storage set of encoded data slices.

3. The method of claim 1 further comprises:

outputting each of the encoded data slices of the storage set of encoded data slices that is selected from the second set of encoded data slices to a dispersed storage network (DSN) memory for storage therein.

4. The method of claim 1, wherein adjusting the error coding dispersal storage function parameters further comprises:

determining desired error coding dispersal storage function parameters based on the performance threshold and the performance based indication;

determining a difference between the desired error coding dispersal storage function parameters and the error coding dispersal storage function parameters to produce a parameters difference; and

adjusting the error coding dispersal storage function parameters based on the parameters difference, wherein determining at least one of the desired error coding dispersal storage function parameters and the parameters difference is based on at least one of;

a set of dispersed storage (DS) units, the error coding dispersal storage function parameters, a vault lookup, a command, a message, a predetermination, a DS unit query, a historical DS unit performance level, an estimated DS unit performance level, storage requirements, and metadata.

5. The method of claim 1 further comprises:

when the performance based indication compares unfavorably with the performance threshold as a result of under-performance, adjusting the error coding dispersal storage function parameters by;

increasing a difference between a decode threshold and a pillar width; and

adjusting an encoding matrix in accordance with the increasing of the difference.

6. The method of claim 1 further comprises:

when the performance based indication compares unfavorably with the performance threshold as a result of over-performance, adjusting the error coding dispersal storage function parameters by;

decreasing a difference between a decode threshold and a pillar width; and

adjusting an encoding matrix in accordance with the increasing of the difference.

7. The method of claim 1, wherein the selecting the storage set of encoded data slices comprises:

selecting the set of encoded data slices; and

selecting at least one encoded data slice of the second set of encoded data slices.

8. A computer comprises:

an interface;

a memory; and

a processing module operable to;

determine a performance based indication regarding storage of a data segment as a set of encoded data slices;

compare the performance based indication with a performance threshold; and

when the performance based indication compares unfavorably with the performance threshold;

decode the set of encoded data slices in accordance with error coding dispersal storage function parameters to reproduce the data segment;

adjust the error coding dispersal storage function parameters based on the unfavorable comparison of the performance based indication with the performance threshold to produce performance adjusted error coding dispersal storage function parameters;

encode the reproduced data segment in accordance with the performance adjusted error coding dispersal storage function parameters to produce a second set of encoded data slices; and

select a storage set of encoded data slices from the set of encoded data slices and the second set of encoded data slices based on a difference between the performance adjusted error coding dispersal storage function parameters and the error coding dispersal storage function parameters.

9. The computer of claim 8, wherein the processing module further functions to:

update a storage location table to associate a corresponding slice name of a set of slice names with a corresponding encoded data slice of the storage set of encoded data slices.

10. The computer of claim 8, wherein the processing module further functions to:

output, via the interface, each of the encoded data slices of the storage set of encoded data slices that is selected from the second set of encoded data slices to a dispersed storage network (DSN) memory for storage therein.

11. The computer of claim 8, wherein the processing module functions to adjust the error coding dispersal storage function parameters by:

determining desired error coding dispersal storage function parameters based on the performance threshold and the performance based indication;

determining a difference between the desired error coding dispersal storage function parameters and the error coding dispersal storage function parameters to produce a parameters difference; and

adjusting the error coding dispersal storage function parameters based on the parameters difference, wherein determining at least one of the desired error coding dispersal storage function parameters and the parameters difference is based on at least one of;

a set of dispersed storage (DS) units, the error coding dispersal storage function parameters, a vault lookup, a command, a message, a predetermination, a DS unit query, a historical DS unit performance level, an estimated DS unit performance level, storage requirements, and metadata.

12. The computer of claim 8, wherein the processing module further functions to:

when the performance based indication compares unfavorably with the performance threshold as a result of under-performance, adjust the error coding dispersal storage function parameters by;

increasing a difference between a decode threshold and a pillar width; and

adjusting an encoding matrix in accordance with the increasing of the difference.

13. The computer of claim 8, wherein the processing module further functions to:

when the performance based indication compares unfavorably with the performance threshold as a result of over-performance, adjust the error coding dispersal storage function parameters by;

decreasing a difference between a decode threshold and a pillar width; and

adjusting an encoding matrix in accordance with the increasing of the difference.

14. The computer of claim 8, wherein the processing module functions to select the storage set of encoded data slices by:

selecting the set of encoded data slices; and

selecting at least one encoded data slice of the second set of encoded data slices.