SELECTING A DATA STORAGE RESOURCE OF A DISPERSED STORAGE NETWORK

• US 20160226522A1
• Filed: 12/02/2015
• Published: 08/04/2016
• Est. Priority Date: 01/30/2015
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Resch, Jason K., Leggette, Wesley, Dhuse, Greg
• Granted Patent: US 9,826,038 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H03M 13/09 Error detection only, e.g. using cyclic redundancy check [CRC] codes or single parity bit
• CPC Class Codes: H03M 13/1515 Reed-Solomon codes
• 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 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 method begins by a computing device of a dispersed storage network (DSN) sending, to a set of storage units of the DSN, a set of write requests regarding a set of encoded data slices, where each write request includes a write set information table that includes a listing of which storage unit of the set of storage units is being sent which encoded data slice of the set of encoded data slices for storage. The method continues with at least some of the storage units receiving write requests of the set of write requests. The method continues with one of the storage units interpreting the write set information table to determine that a particular encoded data slice assigned to a particular storage unit should be stored by a different storage unit and facilitating storing of the particular encoded data slice in the different storage unit.

Claims

1. A method comprises:

sending, by a computing device of a dispersed storage network (DSN) to a set of storage units of the DSN, a set of write requests regarding a set of encoded data slices, wherein a data segment of data is dispersed storage error encoded to produce the set of encoded data slices, wherein each write request of the set of write requests includes a write set information table that includes a listing of which storage unit of the set of storage units is being sent which encoded data slice of the set of encoded data slices for storage therein;

receiving, by at least some of the storage units of the set of storage units, write requests of the set of write requests;

interpreting, by one of the storage units of the at least some of the storage units, the write set information table to determine that a particular encoded data slice assigned to a particular storage unit should be stored by a different storage unit; and

facilitating, by the one of the storage units, storing of the particular encoded data slice in the different storage unit.

2. The method of claim 1 further comprises:

determining, by the one of the storage units as the particular storage unit, a soft failure of the one of the storage units, wherein the one of the storage units is the particular storage unit;

selecting, by the one of the storage units, the different storage unit based on an accessible factor;

sending, by the one of the storage units, a corresponding write request of the set of write requests to the different storage unit, wherein the corresponding write request includes the particular encoded data slice; and

recording, by the one of the storage units, a transfer of the corresponding write request to the different storage unit.

3. The method of claim 2 further comprises:

the soft failure including one or more of;

an overloading condition, a storage capacity condition, a data rate condition, and a memory availability condition; and

the accessible factor including one or more of;

type of coupling between the one of the storage units and the different storage unit, a reliability factor of the different storage unit, a data rate of the different storage unit, and an availability factor of the different storage unit.

4. The method of claim 1 further comprises:

determining, by the one of the storage units, that the particular storage unit is off-line;

selecting, by the one of the storage units, the different storage unit based on an accessible factor;

sending, by the one of the storage units, a corresponding write request of the set of write requests to the different storage unit, wherein the corresponding write request includes the particular encoded data slice; and

recording, by the one of the storage units, the transferring of the corresponding write request to the different storage unit.

5. The method of claim 4 further comprises:

reading, by the one of the storage units, the write request sent to the particular storage unit via a connection between the one of the storage units and the particular storage unit.

6. The method of claim 1 further comprises:

updating, by the one of the storage units, the write set information table to indicate that the particular encoded data slice is being stored by the different storage unit; and

sending, by the one of the storage units, the updated write set information table to the computing device.

7. The method of claim 1 further comprises:

sending, by the computing device, a read request for the particular encoded data slice;

receiving, by the one of the storage units as the particular storage unit, the read request;

forwarding, the read request, to the different storage unit; and

sending, by the different storage unit or the one of the storage units, the particular encoded data slice to the computing device in response to the read request.

8. The method of claim 1 further comprises:

sending, by the computing device, a read request for the particular encoded data slice;

receiving, by the particular storage unit, the read request, wherein the one of the storage units is the different storage unit;

forwarding, the read request, to the different storage unit; and

sending, by the different storage unit or the particular storage unit, the particular encoded data slice to the computing device in response to the read request.

9. A non-transitory computer readable storage medium comprises:

at least one memory section that stores operational instructions that, when executed by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), causes the one or more computing devices to;

sending, by a computing device of the one or more computing devices of the DSN, to a set of storage units of the DSN, a set of write requests regarding a set of encoded data slices, wherein a data segment of data is dispersed storage error encoded to produce the set of encoded data slices, wherein each write request of the set of write requests includes a write set information table that includes a listing of which storage unit of the set of storage units is being sent which encoded data slice of the set of encoded data slices for storage therein;

receive, by at least some of the storage units of the set of storage units, write requests of the set of write requests;

interpret, by one of the storage units of the at least some of the storage units, the write set information table to determine that a particular encoded data slice assigned to a particular storage unit should be stored by a different storage unit; and

facilitate, by the one of the storage units, storing of the particular encoded data slice in the different storage unit.

10. The non-transitory computer readable storage medium of claim 9 further comprises:

the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to;

determine, by the one of the storage units as the particular storage unit, a soft failure of the one of the storage units, wherein the one of the storage units is the particular storage unit;

select, by the one of the storage units, the different storage unit based on an accessible factor;

send, by the one of the storage units, a corresponding write request of the set of write requests to the different storage unit, wherein the corresponding write request includes the particular encoded data slice; and

record, by the one of the storage units, a transfer of the corresponding write request to the different storage unit.

11. The non-transitory computer readable storage medium of claim 10 further comprises:

the soft failure including one or more of;

an overloading condition, a storage capacity condition, a data rate condition, and a memory availability condition; and

the accessible factor including one or more of;

type of coupling between the one of the storage units and the different storage unit, a reliability factor of the different storage unit, a data rate of the different storage unit, and an availability factor of the different storage unit.

12. The non-transitory computer readable storage medium of claim 9 further comprises:

the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to;

determine, by the one of the storage units, that the particular storage unit is off-line;

select, by the one of the storage units, the different storage unit based on an accessible factor;

send, by the one of the storage units, a corresponding write request of the set of write requests to the different storage unit, wherein the corresponding write request includes the particular encoded data slice; and

record, by the one of the storage units, the transferring of the corresponding write request to the different storage unit.

13. The non-transitory computer readable storage medium of claim 9 further comprises:

the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to;

read, by the one of the storage units, the write request sent to the particular storage unit via a connection between the one of the storage units and the particular storage unit.

14. The non-transitory computer readable storage medium of claim 9 further comprises:

the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to;

update, by the one of the storage units, the write set information table to indicate that the particular encoded data slice is being stored by the different storage unit; and

send, by the one of the storage units, the updated write set information table to the computing device.

15. The non-transitory computer readable storage medium of claim 9 further comprises:

the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to;

send, by the computing device, a read request for the particular encoded data slice;

receive, by the one of the storage units as the particular storage unit, the read request;

forward, the read request, to the different storage unit; and

send, by the different storage unit or the one of the storage units, the particular encoded data slice to the computing device in response to the read request.

16. The non-transitory computer readable storage medium of claim 9 further comprises:

the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to;

send, by the computing device, a read request for the particular encoded data slice;

receive, by the particular storage unit, the read request, wherein the one of the storage units is the different storage unit;

forward, the read request, to the different storage unit; and

send, by the different storage unit or the particular storage unit, the particular encoded data slice to the computing device in response to the read request.