Last-resort operations to save at-risk-data

• US 10,432,726 B2
• Filed: 12/14/2017
• Issued: 10/01/2019
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Pure Storage, Inc.
• Inventors: Cocagne, Thomas D.
• Primary Examiner(s): Chaudry, Mujtaba M
• Application Number:
  US15/842,560
• Publication Number:
  US 20180109616A1
• Time in Patent Office: 656 Days
• Field of Search: None
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• 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]

Abstract

A computing device includes an interface configured to interface and communicate with a dispersed storage network (DSN), a memory that stores operational instructions, and processing circuitry operably coupled to the interface and to the memory. The processing circuitry is configured to execute the operational instructions to perform various operations and functions. The computing device detects a total number of errors that is associated with a set of memory devices of one or more sets of storage units (SUs) within a DSN that distributedly store a set of encoded data slices (EDSs). When the total number of errors compares unfavorably to a priority error threshold level, the computing device indicates that a minimum number of error-free EDSs are available of the set of EDSs. The computing device also selects a mechanism for data retention process from a plurality of mechanisms for data retention process and executes it.

Claims

1. A computing device comprising:

an interface configured to interface and communicate with a dispersed or distributed storage network (DSN);

memory that stores operational instructions; and

processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to;

detect a total number of errors that is associated with a set of memory devices of one or more sets of storage units (SUs) within the DSN that distributedly store a set of encoded data slices (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 encoded data slices (EDSs); and

when the total number of errors compares unfavorably to a priority error threshold level;

indicate that a minimum number of error-free EDSs are available of the set of EDSs;

select a mechanism for data retention process from a plurality of mechanisms for data retention process; and

execute the mechanism for data retention process that is selected from the plurality of mechanisms for data retention process.

2. The computing device of claim 1, wherein the total number of errors includes at least one of a memory error associated with a memory device of the set of memory devices or a slice error associated with storage of an EDS of the set of EDSs that is stored in the set of memory devices of the one or more SUs within the DSN.

3. The computing device of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to:

select the mechanism for the data retention process based on at least one of a number of available EDSs, a data type indicator, a data priority indicator, a data owner identifier, a predetermination, a request, or an interpretation of a portion of a system registry.

4. The computing device of claim 1, wherein the plurality of mechanisms for data retention process includes at least one of:

a first mechanism that includes recovering the data segment, encoding the data segment in accordance with the dispersed error encoding parameters or other dispersed error encoding parameters to produce additional EDSs, and storing the additional EDSs within the one or more sets of SUs within the DSN;

a second mechanism that includes recovering the data segment, rebuilding at least one EDS associated with a slice error to generate a rebuilt EDS, and storing the rebuilt EDS within the one or more sets of SUs within the DSN;

a third mechanism that includes recovering the data segment, encoding the data segment in accordance with the dispersed error encoding parameters or other dispersed error encoding parameters to produce to produce a copy of the set of EDSs, and storing the copy of the set of EDSs in another set of SU of the one or more sets of SUs within the DSN;

a fourth mechanism that includes recovering EDSs associated with slice errors from another set of SUs, and storing another copy of the set of EDS within the one or more sets of SUs within the DSN; and

a fifth mechanism that includes temporarily suspending access to the set of memory devices and prioritizing rebuilding of EDSs within the set of EDSs associated with slice errors.

5. The computing device of claim 1, wherein:

a decode threshold number of EDSs are needed to recover the data segment;

a read threshold number of EDSs provides for reconstruction of the data segment;

a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN;

the set of EDSs is of pillar width and includes a pillar number of EDSs;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number.

6. The computing device of claim 1, wherein the computing device is located at a first premises that is remotely located from a second premises of at least one SU of the one or more sets of SUs within the DSN.

7. The computing device of claim 1 further comprising:

a SU of the one or more sets of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

8. The computing device of claim 1, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN).

9. A computing device comprising:

an interface configured to interface and communicate with a dispersed or distributed storage network (DSN);

memory that stores operational instructions; and

processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to;

detect a total number of errors that is associated with a set of memory devices of one or more sets of storage units (SUs) within the DSN that distributedly store a set of encoded data slices (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 encoded data slices (EDSs), wherein the total number of errors includes at least one of a memory error associated with a memory device of the set of memory devices or a slice error associated with storage of an EDS of the set of EDSs that is stored in the set of memory devices of the one or more SUs within the DSN; and

when the total number of errors compares unfavorably to a priority error threshold level;

indicate that a minimum number of error-free EDSs are available of the set of EDSs;

select a mechanism for data retention process from a plurality of mechanisms for data retention process based on at least one of a number of available EDSs, a data type indicator, a data priority indicator, a data owner identifier, a predetermination, a request, or an interpretation of a portion of a system registry; and

execute the mechanism for data retention process that is selected from the plurality of mechanisms for data retention process.

10. The computing device of claim 9, wherein the plurality of mechanisms for data retention process includes at least one of:

a first mechanism that includes recovering the data segment, encoding the data segment in accordance with the dispersed error encoding parameters or other dispersed error encoding parameters to produce additional EDSs, and storing the additional EDSs within the one or more sets of SUs within the DSN;

a second mechanism that includes recovering the data segment, rebuilding at least one EDS associated with a slice error to generate a rebuilt EDS, and storing the rebuilt EDS within the one or more sets of SUs within the DSN;

a third mechanism that includes recovering the data segment, encoding the data segment in accordance with the dispersed error encoding parameters or other dispersed error encoding parameters to produce to produce a copy of the set of EDSs, and storing the copy of the set of EDSs in another set of SU of the one or more sets of SUs within the DSN;

a fourth mechanism that includes recovering EDSs associated with slice errors from another set of SUs, and storing another copy of the set of EDS within the one or more sets of SUs within the DSN; and

a fifth mechanism that includes temporarily suspending access to the set of memory devices and prioritizing rebuilding of EDSs within the set of EDSs associated with slice errors.

11. The computing device of claim 9, wherein:

a decode threshold number of EDSs are needed to recover the data segment;

a read threshold number of EDSs provides for reconstruction of the data segment;

a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN;

the set of EDSs is of pillar width and includes a pillar number of EDSs;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number.

12. The computing device of claim 9 further comprising:

a SU of the one or more sets of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

13. The computing device of claim 9, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN).

14. A method for execution by a computing device, the method comprising:

detecting a total number of errors that is associated with a set of memory devices of one or more sets of storage units (SUs) within a dispersed or distributed storage network (DSN) that distributedly store a set of encoded data slices (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 encoded data slices (EDSs); and

when the total number of errors compares unfavorably to a priority error threshold level;

indicating that a minimum number of error-free EDSs are available of the set of EDSs;

selecting a mechanism for data retention process from a plurality of mechanisms for data retention process; and

executing, via an interface of the computing device that is configured to interface and communicate with a dispersed or distributed storage network (DSN), the mechanism for data retention process that is selected from the plurality of mechanisms for data retention process.

15. The method of claim 14, wherein the total number of errors includes at least one of a memory error associated with a memory device of the set of memory devices or a slice error associated with storage of an EDS of the set of EDSs that is stored in the set of memory devices of the one or more SUs within the DSN.

16. The method of claim 14 further comprising:

selecting the mechanism for the data retention process based on at least one of a number of available EDSs, a data type indicator, a data priority indicator, a data owner identifier, a predetermination, a request, or an interpretation of a portion of a system registry.

17. The method of claim 14, wherein the plurality of mechanisms for data retention process includes at least one of:

a first mechanism that includes recovering the data segment, encoding the data segment in accordance with the dispersed error encoding parameters or other dispersed error encoding parameters to produce additional EDSs, and storing the additional EDSs within the one or more sets of SUs within the DSN;

a second mechanism that includes recovering the data segment, rebuilding at least one EDS associated with a slice error to generate a rebuilt EDS, and storing the rebuilt EDS within the one or more sets of SUs within the DSN;

a third mechanism that includes recovering the data segment, encoding the data segment in accordance with the dispersed error encoding parameters or other dispersed error encoding parameters to produce to produce a copy of the set of EDSs, and storing the copy of the set of EDSs in another set of SU of the one or more sets of SUs within the DSN;

a fourth mechanism that includes recovering EDSs associated with slice errors from another set of SUs, and storing another copy of the set of EDS within the one or more sets of SUs within the DSN; and

a fifth mechanism that includes temporarily suspending access to the set of memory devices and prioritizing rebuilding of EDSs within the set of EDSs associated with slice errors.

18. The method of claim 14, wherein:

a decode threshold number of EDSs are needed to recover the data segment;

a read threshold number of EDSs provides for reconstruction of the data segment;

a write threshold number of EDSs provides for a successful transfer of the set of EDSs from a first at least one location in the DSN to a second at least one location in the DSN;

the set of EDSs is of pillar width and includes a pillar number of EDSs;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number.

19. The method of claim 14, wherein the computing device includes a SU of the one or more sets of SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

20. The method of claim 14, wherein the DSN includes at least one of a wireless communication system, a wire lined communication system, a non-public intranet system, a public internet system, a local area network (LAN), or a wide area network (WAN).