Expanding slice count in response to low-level failures

• US 10,209,921 B2
• Filed: 08/27/2016
• Issued: 02/19/2019
• Est. Priority Date: 09/24/2015
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Peake, Andrew G.
• Primary Examiner(s): Lamarre, Guy J
• Application Number:
  US15/249,353
• Publication Number:
  US 20170091036A1
• Time in Patent Office: 906 Days
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0614 Improving the reliability of storage systems
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0661 Format or protocol conversion arrangements
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 8/65 Updates security arrangements therefor G06F21/57
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• CPC Class Codes: H03M 13/154 Error and erasure correction, e.g. by using the error and erasure locator or Forney polynomial
• CPC Class Codes: H03M 13/3761 using code combining, i.e. using combining of codeword portions which may have been transmitted separately, e.g. Digital Fountain codes, Raptor codes or Luby Transform [LT] codes
• CPC Class Codes: H04L 63/061 for key exchange, e.g. in peer-to-peer networks cryptographic mechanisms or cryptographic arrangements for key agreement H04L9/0838
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• 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 67/34 involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 67/60 Scheduling or organising the servicing of application requests, e.g. requests for application data transmissions using the analysis and optimisation of the required network resources admission control or resource allocation H04L47/70

Abstract

A method for execution by a computing device of a dispersed storage network (DSN). The method begins with identifying an encoded data slice for rebuilding, wherein a data segment of a data object is dispersed storage error encoded to produce a set of encoded data slices that is stored in a set of storage units of the DSN, wherein the set of encoded data slices includes the encoded data slice, wherein in a storage unit of the set of storage units includes a memory device that stores the encoded data slice. The method continues by identifying an issue with the memory device and by identifying sets of encoded data slices. The method continues by generating an additional encoded data slice for each of the sets of encoded data slices to produce a group of encoded data slices and storing the group of encoded data slices in memory of the DSN.

Claims

1. A method for execution by a computing device of a dispersed storage network (DSN), the method comprises:

identifying an encoded data slice for rebuilding, wherein a data segment of a data object is dispersed storage error encoded to produce a set of encoded data slices that is stored in a set of storage units of the DSN, wherein the set of encoded data slices includes the encoded data slice for rebuilding, wherein in a storage unit of the set of storage units includes a plurality of memory devices, wherein a memory device of the plurality of memory devices stores the encoded data slice; and

determining whether the memory device has an issue;

when the memory device has the issue;

identifying sets of encoded data slices, wherein a first encoded data slice of each of the sets of encoded data slices is stored in the memory device;

generating at least one additional encoded data slice for each of the sets of encoded data slices to produce at least one group of encoded data slices; and

storing the at least one group of encoded data slices in at least one other memory device of the DSN.

2. The method of claim 1, wherein the determining whether the memory device has the issue comprises one or more of:

receiving a message indicating the memory device has the issue;

determining the age of the memory device has exceeded an age threshold;

accessing a maintenance schedule, wherein the memory device is identified for replaced in the maintenance schedule; and

determining the storage unit is inaccessible.

3. The method of claim 1, wherein the identifying the sets of encoded data slices comprises:

sending a list request to the storage unit regarding the at least one group of encoded data slices;

receiving a list of a group of slice names for the at least one group of encoded data slices; and

interpreting the group of slices names to identify the sets of encoded data slices.

4. The method of claim 1, wherein the generating the at least one additional encoded data slice for each of the sets of encoded data slices comprises:

determining a number of additional encoded data slices to generate for the each of the sets of encoded data slices, wherein the number is based on a comparison of one or more of;

a number of available encoded data slices in each of the sets of encoded data slices;

a write threshold number of the sets of encoded data slices;

a read threshold number of the sets of encoded data slices;

a decode threshold number of the sets of encoded data slices; and

a pillar width number of the sets of encoded data slices.

5. The method of claim 4, wherein the determining the number further comprises:

determining a cost associated with an expanded set of storage units, wherein the expanded set of storage units include at least one of the set of storage units and one or more other storage units;

when the cost is below a first cost threshold, generating a first number of additional encoded data slices;

when the cost is equal to or above the first cost threshold, generating a second number of additional encoded data slices, wherein the second number is less than the first number, and wherein the cost associated with the expanded set of storage units includes on one or more of;

historical performance;

bandwidth; and

available storage.

6. The method of claim 1 further comprises:

rebuilding the encoded data slice.

7. The method of claim 1, wherein the storing the at least one group of encoded data slices comprises:

storing the at least one group of encoded data slices in one or more other memory devices of the plurality of memory devices of the storage unit.

8. The method of claim 1, wherein the storing the at least one group of encoded data slices comprises:

storing the at least one group of encoded data slices in another storage unit, wherein the set of storage units is expanded to include the other storage unit.

9. A computing device comprises:

an interface;

a memory; and

a processing module, wherein the processing module is operably coupled the memory and the interface, wherein the processing module is operable to;

identify an encoded data slice for rebuilding, wherein a data segment of a data object is dispersed storage error encoded to produce a set of encoded data slices that is stored in a set of storage units of a dispersed storage network (DSN), wherein the set of encoded data slices includes the encoded data slice for rebuilding, wherein in a storage unit of the set of storage units includes a plurality of memory devices, wherein a memory device of the plurality of memory devices stores the encoded data slice; and

determine whether the memory device has an issue;

when the memory device has the issue;

identify sets of encoded data slices, wherein a first encoded data slice of each of the sets of encoded data slices is stored in the memory device;

generate at least one additional encoded data slice for each of the sets of encoded data slices to produce at least one group of encoded data slices; and

store, via the interface, the at least one group of encoded data slices in at least one other memory device of the DSN.

10. The computing device of claim 9, wherein the processing module determines whether the memory device has the issue by one or more of:

receiving a message indicating the memory device has the issue;

determining the age of the memory device has exceeded an age threshold;

accessing a maintenance schedule, wherein the memory device is identified for replaced in the maintenance schedule; and

determining the storage unit is inaccessible.

11. The computing device of claim 9, wherein the processing module is operable to identify the sets of encoded data slices by:

sending, via the interface, a list request to the storage unit regarding the at least one group of encoded data slices;

receiving, via the interface, a list of a group of slice names for the at least one group of encoded data slices; and

interpreting the group of slices names to identify the sets of encoded data slices.

12. The computing device of claim 9, wherein the processing module is further operable to generate the at least one additional encoded data slice for each of the sets of encoded data slices by:

determining a number of additional encoded data slices to generate for the each of the sets of encoded data slices, wherein the number is based on a comparison of one or more of;

a number of available encoded data slices in each of the sets of encoded data slices;

a write threshold number of the sets of encoded data slices;

a read threshold number of the sets of encoded data slices;

a decode threshold number of the sets of encoded data slices; and

a pillar width number of the sets of encoded data slices.

13. The computing device of claim 12, wherein the processing module is further operable to determine the number by:

determining a cost associated with an expanded set of storage units, wherein the expanded set of storage units include at least one of the set of storage units and one or more other storage units;

when the cost is below a first cost threshold, generating a first number of additional encoded data slices;

when the cost is equal to or above the first cost threshold, generating a second number of additional encoded data slices, wherein the second number is less than the first number, and wherein the cost associated with the expanded set of storage units includes on one or more of;

historical performance;

bandwidth; and

available storage.

14. The computing device of claim 9, wherein the processing module is further operable to:

rebuild the encoded data slice.

15. The computing device of claim 9, wherein the processing module is further operable to store the at least one group of encoded data slices by:

storing, via the interface, the at least one group of encoded data slices in one or more other memory devices of the plurality of memory devices of the storage unit.

16. The computing device of claim 9, wherein the processing module is further operable to store the at least one group of encoded data slices by:

storing the at least one group of encoded data slices in another storage unit, wherein the set of storage units is expanded to include the other storage unit.