Rebuilding a data revision in a dispersed storage network
View Patent ↗A method begins by a processing module storing a set of encoded data slices in storage units. A data segment of data is encoded, in accordance with dispersed storage error encoding parameters, to produce the set of encoded data slices. The dispersed storage error encoding parameters include a decode threshold number and a pillar width number, which is at least twice the decode threshold number. The method continues with the processing module processing a first request for retrieval of the data segment by retrieving a first sub-set of encoded data slices, which includes the decode threshold number, and decoding them to produce a first recovered data segment. The method continues with the processing module processing a second request for retrieval of the data segment by retrieving a second sub-set of encoded data slices, which includes the decode threshold number, and decoding them to produce a second recovered data segment.
1. A method for execution by a processing module of a computing device, the method comprises the steps of:
storing a set of encoded data slices in storage units of a dispersed storage network, wherein a data segment of data is encoded, in accordance with dispersed storage error encoding parameters, to produce the set of encoded data slices, wherein the dispersed storage error encoding parameters include a pillar width number that represents a total number of encoded data slices in the set of encoded data slices and a decode threshold number with represents a minimum number of encoded data slices that is needed to recover the data segment, and wherein the pillar width number is at least twice the decode threshold number;
processing a first request for retrieval of the data segment by:
retrieving a first sub-set of encoded data slices of the set of encoded data slices, wherein the first sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the first sub-set of encoded data slices to produce a first recovered data segment; and
processing a second request for retrieval of the data segment by:
retrieving a second sub-set of encoded data slices of the set of encoded data slices, wherein the second sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the second sub-set of encoded data slices to produce a second recovered data segment.
2. The method of claim 1 further comprises:
determining that the first sub-set of encoded data slices and the second sub-set of encoded data slices have different revision levels; and
determining a remedy for the difference in revision levels.
3. The method of claim 2 , wherein the remedy comprises one or more of:
rebuilding the first or the second sub-set of encoded data slices;
maintaining the first and second sub-set of encoded data slices; and
deleting the first or the second sub-set of encoded data slices.
4. The method of claim 1 further comprises:
processing a third request for retrieval of the data segment by:
retrieving a third sub-set of encoded data slices of the set of encoded data slices, wherein the third sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the third sub-set of encoded data slices to produce a third recovered data segment.
5. The method of claim 1 further comprises:
updating the first sub-set of encoded data slices with a more current revision level.
6. A computer comprises:
an interface;
a memory; and
a processing module operable to:
store a set of encoded data slices in storage units of a dispersed storage network, wherein a data segment of data is encoded, in accordance with dispersed storage error encoding parameters, to produce the set of encoded data slices, wherein the dispersed storage error encoding parameters include a pillar width number that represents a total number of encoded data slices in the set of encoded data slices and a decode threshold number with represents a minimum number of encoded data slices that is needed to recover the data segment, and wherein the pillar width number is at least twice the decode threshold number;
process a first request for retrieval of the data segment by:
retrieving a first sub-set of encoded data slices of the set of encoded data slices, wherein the first sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the first sub-set of encoded data slices to produce a first recovered data segment; and
process a second request for retrieval of the data segment by:
retrieving a second sub-set of encoded data slices of the set of encoded data slices, wherein the second sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the second sub-set of encoded data slices to produce a second recovered data segment.
7. The computer of claim 6 , wherein the processing module is further operable to:
determine that the first sub-set of encoded data slices and the second sub-set of encoded data slices have different revision levels; and
determine a remedy for the difference in revision levels.
8. The computer of claim 7 , wherein the remedy comprises one or more of:
rebuilding the first or the second sub-set of encoded data slices;
maintaining the first and second sub-set of encoded data slices; and
deleting the first or the second sub-set of encoded data slices.
9. The computer of claim 6 , wherein the processing module is further operable to:
process a third request for retrieval of the data segment by:
retrieving a third sub-set of encoded data slices of the set of encoded data slices, wherein the third sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the third sub-set of encoded data slices to produce a third recovered data segment.
10. The computer of claim 6 , wherein the processing module is further operable to:
update the first sub-set of encoded data slices with a more current revision level.
11. A non-transitory computer readable storage device comprises:
a first memory section that stores operational instructions that, when executed by a computing device, causes the computing device to:
store a set of encoded data slices in storage units of a dispersed storage network, wherein a data segment of data is encoded, in accordance with dispersed storage error encoding parameters, to produce the set of encoded data slices, wherein the dispersed storage error encoding parameters include a pillar width number that represents a total number of encoded data slices in the set of encoded data slices and a decode threshold number with represents a minimum number of encoded data slices that is needed to recover the data segment, and wherein the pillar width number is at least twice the decode threshold number; and
a second memory section that stores operational instructions that, when executed by the computing device, causes the computing device to:
process a first request for retrieval of the data segment by:
retrieving a first sub-set of encoded data slices of the set of encoded data slices, wherein the first sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the first sub-set of encoded data slices to produce a first recovered data segment; and
process a second request for retrieval of the data segment by:
retrieving a second sub-set of encoded data slices of the set of encoded data slices, wherein the second sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the second sub-set of encoded data slices to produce a second recovered data segment.
12. The non-transitory computer readable storage device of claim 11 further comprises:
a third memory section that stores operational instructions that, when executed by the computing device, causes the computing device to:
determine that the first sub-set of encoded data slices and the second sub-set of encoded data slices have different revision levels; and
determine a remedy for the difference in revision levels.
13. The non-transitory computer readable storage device of claim 12 , wherein the remedy comprises one or more of:
rebuilding the first or the second sub-set of encoded data slices;
maintaining the first and second sub-set of encoded data slices; and
deleting the first or the second sub-set of encoded data slices.
14. The non-transitory computer readable storage device of claim 11 , wherein the second memory section further stores operational instructions that, when executed by the computing device, causes the computing device to:
process a third request for retrieval of the data segment by:
retrieving a third sub-set of encoded data slices of the set of encoded data slices, wherein the third sub-set of encoded data slices includes the decode threshold number of encoded data slices;
decoding the third sub-set of encoded data slices to produce a third recovered data segment.
15. The non-transitory computer readable storage device of claim 11 further comprises:
a third memory section that stores operational instructions that, when executed by the computing device, causes the computing device to:
update the first sub-set of encoded data slices with a more current revision level.