Proxying slice access requests during a data evacuation

Patent metadata

Field	Value
Publication number	US-10073736-B2
Application number	US-201615220983-A
Country	US
Kind code	B2
Filing date	Jul 27, 2016
Priority date	Jul 31, 2015
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

A method begins by a processing module receiving a checked write slice request from a requesting entity. The method continues by determining that locally stored encoded data slices do not include the requested encoded data slice. The method continues by identifying an alternate location for the requested encoded data slice. The method continues by determining whether the alternate location is associated with storage of the encoded data slice. The method continues when the alternate location is associated with the storage of the encoded data slice, by issuing a favorable checked write slice response to a requesting entity. The method can include facilitating transfer of the requested encoded data slice from the alternate location to the storage unit for storage.

First claim

What is claimed is:

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:
selecting a second storage unit based on a decentralized agreement module decision decided by a decentralized agreement module, wherein the decentralized agreement module receives a ranked scoring information request from a requestor with regards to a set of candidate storage unit resources and, for each of the candidate storage unit resources, the decentralized agreement module performs a deterministic function on a location identifier (ID) of the candidate storage unit resource and an asset ID of the ranked scoring information request;
initiating an evacuation of encoded data slices from a first storage unit to the second storage unit;
receiving, at the second storage unit, a checked write slice request from a requesting entity, the checked write slice request including a requested encoded data slice;
determining that locally stored encoded data slices do not include the requested encoded data slice;
identifying an alternate location for the requested encoded data slice;
determining whether the alternate location is associated with storage of the requested encoded data slice; and
when the alternate location is associated with storage of the requested encoded data slice, issuing a favorable checked write slice response to the requesting entity.

2. The method of claim 1 , wherein the checked write slice request further includes one or more of: slice name, encoded data slice for storage, or a revision level.

3. The method of claim 2 further comprising generating a response to include one or more of: a code associated with the checked write slice request, a name of the encoded data slice, or a revision level.

4. The method of claim 1 , wherein the determining that locally stored encoded data slices do not include the requested encoded data slice includes one or more of: performing a lookup or interpreting a query response.

5. The method of claim 1 , wherein the determining whether the alternate location is associated with the requested encoded data slice includes one or more of: issuing a checked request to the alternate location or interpreting a checked response.

6. The method of claim 1 further comprising facilitating transfer of the requested encoded data slice from the alternate location to a location of the locally stored encoded data slices for storage.

7. A computing device of a group of computing devices of a dispersed storage network (DSN), the computing device comprises:
an interface;
a local memory; and
a processing module operably coupled to the interface and the local memory, wherein the processing module functions to:
select a second storage unit based on a decentralized agreement module decision decided by a decentralized agreement module, wherein the decentralized agreement module receives a ranked scoring information request from a requestor with regards to a set of candidate storage unit resources and, for each of the candidate storage unit resources, the decentralized agreement module performs a deterministic function on a location identifier (ID) of the candidate storage unit resource and an asset ID of the ranked scoring information request;
initiate an evacuation of encoded data slices from a first storage unit to the second storage unit;
receive, at the second storage unit, a checked write slice request from a requesting entity, the checked write slice request including a requested encoded data slice;
determine whether the alternate location is associated with storage of the requested encoded data slice; and
when the alternate location is associated with storage of the requested encoded data slice, issue a favorable checked write slice response to the requesting entity.

8. The computing device of claim 7 , wherein the checked write slice request further includes one or more of: slice name, encoded data slice for storage, or a revision level.

9. The computing device of claim 7 further comprising generating a response to include one or more of: a code associated with the checked write slice request, a name of the encoded data slice, or a revision level.

10. The computing device of claim 7 , wherein the determining that locally stored encoded data slices do not include the requested encoded data slice includes one or more of: performing a lookup or interpreting a query response.

11. The computing device of claim 7 , wherein the determining whether the alternate location is associated with the requested encoded data slice includes one or more of: issuing a checked request to the alternate location or interpreting a checked response.

12. The computing device of claim 7 further comprising facilitating transfer of the requested encoded data slice from the alternate location to a location of the locally stored encoded data slices for storage.

13. 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:
selecting a second storage unit based on a decentralized agreement module decision decided by a decentralized agreement module, wherein the decentralized agreement module receives a ranked scoring information request from a requestor with regards to a set of candidate storage unit resources and, for each of the candidate storage unit resources, the decentralized agreement module performs a deterministic function on a location identifier (ID) of the candidate storage unit resource and an asset ID of the ranked scoring information request;
receiving, during an evacuation of encoded data slices from a first storage unit to the second storage unit, a checked write slice request at the second storage unit from a requesting entity, the checked write slice request including a requested encoded data slice;
determining that locally stored encoded data slices do not include the requested encoded data slice;
identifying an alternate location for the requested encoded data slice;
determining whether the alternate location is associated with storage of the requested encoded data slice; and
when the alternate location is associated with storage of the requested encoded data slice, issuing a favorable checked write slice response to the requesting entity.

14. The method of claim 13 , wherein the checked write slice request further includes one or more of: slice name, encoded data slice for storage, or a revision level.

15. The method of claim 13 further comprising generating a response to include one or more of: a code associated with the checked write slice request, a name of the encoded data slice, or a revision level.

16. The method of claim 13 , wherein the determining that locally stored encoded data slices do not include the requested encoded data slice includes one or more of: performing a lookup or interpreting a query response.

17. The method of claim 13 , wherein the determining whether the alternate location is associated with the requested encoded data slice includes one or more of: issuing a checked request to the alternate location or interpreting a checked response.

18. The method of claim 13 further comprising facilitating transfer of the requested encoded data slice from the alternate location to a location of the locally stored encoded data slices for storage.

Assignees

• IBM

Inventors

• Kazi Asimuddin
• Mcshane Niall J
• Motwani Manish
• Niedbala Michael J

Classifications

• G06F3/0689

  Disk arrays, e.g. RAID, JBOD · CPC title

• G06F3/0643

  Management of files · CPC title

• G06F11/3034

  where the computing system component is a storage system, e.g. DASD based or network based (digital input from or digital output to record carriers G06F3/06; digital recording or reproducing G11B20/18; 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], H04L67/1097) · CPC title

• G06F11/1076

  Parity data used in redundant arrays of independent storages, e.g. in RAID systems · CPC title

• G06F13/4282

  on a serial bus, e.g. I2C bus, SPI bus (on daisy chain buses G06F13/4247) · CPC title