Method for performing in-place disk format changes in a distributed storage network

• US 10,133,634 B2
• Filed: 03/30/2017
• Issued: 11/20/2018
• Est. Priority Date: 03/30/2017
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Motwani, Manish
• Primary Examiner(s): Tabone, Jr., John J
• Application Number:
  US15/473,942
• Publication Number:
  US 20180285196A1
• Time in Patent Office: 600 Days
• Field of Search: 714764, 714702, 714718, 714751, 714752, 714763, 714769, 714770, 714773, 714799, 714 61, 714 62, 714 622, 714 624, 714 4, 711111, 711114, 711170, 709231, 707822
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk

Abstract

A method begins by processing modules in a dispersed storage network (DSN) identifying a memory device having a legacy slice storage format (SSF) to a second SSF and that includes a first encoded data slice (EDS) of a set of EDSs. When at least a predetermined threshold number of EDSs of the set of EDSs are included within one or storage units (SUs) excluding the first EDS the method continues by transitioning the first SSF of the memory device to the second SSF, and performing a rebuilding process using the at least the decode threshold number of EDSs of the set of EDSs to generate a rebuilt first EDS. The method continues by storing the rebuilt first EDS within the memory device to replace the first EDS that was deleted during the transitioning.

Claims

1. A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises:

identifying a memory device having a first slice storage format (SSF) that is a legacy SSF to a second SSF within the DSN that includes a first encoded data slice (EDS) of a set of EDSs, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce the set of EDSs;

when at least a predetermined threshold number of EDSs of the set of EDSs are included within one or more storage units (SUs) within the DSN excluding the first EDS of the set of EDSs, transitioning the first SSF of the memory device to the second SSF, wherein the first EDS of the set of EDSs having the first SSF is deleted during the transitioning;

retrieving at least a decode threshold number of EDSs of the set of EDSs from the one or more SUs within the DSN;

performing a rebuilding process using the at least the decode threshold number of EDSs of the set of EDSs to generate a rebuilt first EDS; and

storing the rebuilt first EDS within the memory device to replace the first EDS of the set of EDSs having the first SSF that was deleted during the transitioning.

2. The method of claim 1, wherein the first and second SSFs are on-disk data formats for error encoded data slices.

3. The method of claim 2, wherein the first SSF is in accordance with at least one version of a Linux extended file system.

4. The method of claim 2, wherein the second SSF is in accordance with a pre-allocation of a predetermined number of files on the memory device.

5. The method of claim 2, wherein the second SSF is not in accordance a version of a Linux extended file system.

6. The method of claim 1, further comprises:

delaying the transitioning the first SSF of the memory device to the second SSF until each of the encoded data slice (EDS) of the set of EDSs is determined by the one or more processing modules of the one or more computing devices of the DSN to require rebuilding.

7. The method of claim 1 further comprises:

identifying another memory device within the DSN that includes a second encoded data slice (EDS) of the set of EDSs having a first slice storage format (SSF) that is a legacy SSF to a second SSF;

when at least a predetermined threshold number of EDSs of the set of EDSs are included within the one or more storage units (SUs) within the DSN excluding the second EDS of the set of EDSs;

transitioning the first SSF of the another memory device to the second SSF, wherein the second EDS of the set of EDSs having the first SSF is deleted during the transitioning;

retrieving at least a decode threshold number of EDSs of the set of EDSs from the one or more storage units (SUs) within the DSN;

performing a rebuilding process using the at least the decode threshold number of EDSs of the set of EDSs to generate a rebuilt second EDS; and

storing the rebuilt second EDS within the another memory device to replace the second EDS of the set of EDSs having the first SSF that was deleted during the transitioning.

8. A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises:

identifying a first memory device having a first slice storage format (SSF) that is a legacy SSF to a second SSF within the DSN that includes a first encoded data slice (EDS) of a set of EDSs, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce the set of EDSs;

when at least a predetermined threshold number of EDSs of the set of EDSs are included within one or more storage units (SUs) within the DSN excluding the first EDS of the set of EDSs, transitioning the first SSF of the first memory device to the second SSF, wherein the first EDS of the set of EDSs having the first SSF is deleted during the transitioning;

identifying a second memory device having a first slice storage format (SSF) that is a legacy SSF to a second SSF within the DSN that includes a second encoded data slice (EDS) of the set of EDSs having a first slice storage format (SSF) that is a legacy SSF to a second SSF;

transferring the second encoded data slice (EDS) of the set of EDSs having a first slice storage format (SSF) that is a legacy SSF to a second SSF to the first memory device; and

transitioning the first SSF of the second memory device to the second SSF.

9. The method of claim 8, wherein the first and second SSFs are on-disk data formats for error encoded data slices.

10. The method of claim 9, wherein the first SSF is in accordance with at least one version of a Linux extended file system.

11. The method of claim 9, wherein the second SSF is in accordance with a pre-allocation of a predetermined number of files on the first memory device.

12. The method of claim 9, wherein the second SSF is not in accordance a version of a Linux extended file system.

13. The method of claim 8, further comprises:

delaying the transitioning the first SSF of the first memory device to the second SSF until each of the encoded data slice (EDS) of the set of EDSs is determined by the one or more processing modules of the one or more computing devices of the DSN to require rebuilding.

14. The method of claim 8 further comprises:

identifying a third memory device having a first slice storage format (SSF) that is a legacy SSF to the second SSF within the DSN that includes a third (EDS) of the set of EDSs;

transferring the third EDS of the set of EDSs having a first slice storage format (SSF) that is a legacy SSF to a second SSF to the second memory device; and

transitioning the first SSF of the third memory device to the second SSF.

15. A dispersed storage (DS) module in a distributed storage network (DSN) comprises:

a first module, when operable within a computing device, causes the computing device to;

identify a first memory device having a first slice storage format (SSF) that is a legacy SSF to a second SSF within the DSN that includes a first encoded data slice (EDS) of a set of EDSs, wherein a data object is segmented into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed error encoded in accordance with dispersed error encoding parameters to produce the set of EDSs;

a second module, when operable within the computing device, causes the computing device to;

when at least a predetermined threshold number of EDSs of the set of EDSs are included within one or more storage units (SUs) within the DSN excluding the first EDS of the set of EDSs, transition the first SSF of the first memory device to the second SSF, wherein the first EDS of the set of EDSs having the first SSF is deleted during the transitioning;

a third module, when operable within the computing device, causes the computing device to;

identify a second memory device having a first slice storage format (SSF) that is a legacy SSF to a second SSF within the DSN that includes a second encoded data slice (EDS) of the set of EDSs having a first slice storage format (SSF) that is a legacy SSF to a second SSF;

a fourth module, when operable within the computing device, causes the computing device to;

transfer the second encoded data slice (EDS) of the set of EDSs having a first slice storage format (SSF) that is a legacy SSF to a second SSF to the first memory device; and

a fifth module, when operable within the computing device, causes the computing device to;

transition the first SSF of the second memory device to the second SSF.

16. The dispersed storage (DS) module of claim 15, wherein the first and second SSFs are on-disk data formats for dispersed error encoded data slices.

17. The dispersed storage (DS) module of claim 16, wherein the first SSF is in accordance with at least one version of a Linux extended file system.

18. The dispersed storage (DS) module of claim 16, wherein the second SSF is in accordance with a pre-allocation of a predetermined number of files on the memory device.

19. The dispersed storage (DS) module of claim 16, wherein the second SSF is not in accordance a version of a Linux extended file system.

20. The dispersed storage (DS) module of claim 15 further comprises:

a sixth module, when operable within the computing device, causes the computing device to;

delay the transitioning the first SSF of the memory device to the second SSF until each of the encoded data slice (EDS) of the set of EDSs is determined by the one or more processing modules of the one or more computing devices of the DSN to require rebuilding.