Utilizing reallocation via a decentralized, or distributed, agreement protocol (DAP) for storage unit (SU) replacement

• US 9,992,063 B2
• Filed: 07/18/2016
• Issued: 06/05/2018
• Est. Priority Date: 07/18/2016
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Baptist, Andrew D., Motwani, Manish, Resch, Jason K.
• Primary Examiner(s): Keehn, Richard G
• Application Number:
  US15/212,749
• Publication Number:
  US 20180019916A1
• Time in Patent Office: 687 Days
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: H04L 41/0813 characterised by the conditions triggering a change of settings
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 49/901 using storage descriptor, e.g. read or write pointers
• 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 67/146 Markers for unambiguous identification of a particular session, e.g. session cookie or URL-encoding
• CPC Class Codes: H04L 67/148 Migration or transfer of sessions

Abstract

Based on a system configuration change (e.g., of a Decentralized, or Distributed, Agreement Protocol (DAP)) within a dispersed storage network (DSN) (e.g., from a first to a second system configuration of the DAP), a computing device directs a storage unit to be replaced (SUTBR) to transfer encoded data slices (EDSs) stored therein to a replacement storage unit (RSU). During transfer of the EDSs (e.g., from SUTBR to RSU), the computing device directs the SUTBR to service read and/or write requests for EDS(s) stored therein to operate based on a first system configuration of the DAP. When the EDSs have been successfully transferred from the SUTBR to the RSU, the computing device directs the RSU to service read and/or write requests for the EDS(s) stored therein to operate based on a second system configuration of the DAP.

Claims

1. A computing device comprising:

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

memory that stores operational instructions; and

a processing module operably coupled to the interface and to the memory, wherein the processing module, when operable within the computing device based on the operational instructions, is configured to;

detect a change from a first system configuration of a Decentralized, or Distributed, Agreement Protocol (DAP) to a second system configuration of the DAP based on a storage unit to be replaced (SUTBR) within a plurality of storage units (SUs) within the DSN, wherein the first system configuration of the DAP and the second system configuration of the DAP respectively provide for deterministic calculation of locations of encoded data slice (EDS) sets that correspond respectively to a plurality of data segments of a data object that are distributedly stored across the plurality of storage units (SUs) within the DSN, wherein the data object is segmented into the 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 a set of EDSs of the EDS sets that is of pillar width having a plurality of EDS names, wherein a read threshold number of EDSs of the set of EDSs provides for reconstruction of the data segment, wherein a write threshold number of EDSs of the set 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, wherein the data object is associated with a unique source name, and wherein each EDS name of the plurality of EDS names includes a reference to the unique source name;

direct the SUTBR to transfer a plurality of EDSs stored within the SUTBR to a replacement storage unit (RSU) for storage within the RSU;

during transfer of the plurality of EDSs from the SUTBR to the RSU;

direct the plurality of SUs to operate based on the first system configuration of the DAP; and

direct the SUTBR to service read requests and write requests from one or more other computing devices for at least one EDS of the plurality of EDSs based on the first system configuration of the DAP; and

when the plurality of EDSs have been successfully transferred from the SUTBR to the RSU;

direct the plurality of SUs to operate based on the second system configuration of the DAP; and

direct the RSU to service read and write requests from the one or more other computing devices for the at least one EDS of the plurality of EDSs based on the second system configuration of the DAP.

2. The computing device of claim 1, wherein:

the DAP, when executed using the unique source name and coefficients regarding the plurality of SUs of the DSN, produces a ranking of the plurality of SUs that deterministically identifies those SUs of the plurality of SUs that store the EDS sets including the set of EDSs of the EDS sets; and

the processing module, when operable within the computing device based on the operational instructions, is further configured to update the coefficients regarding the plurality of SUs based on the change from the first system configuration of the DAP to the second system configuration of the DAP.

3. The computing device of claim 1, wherein the processing module, when operable within the computing device based on the operational instructions, is further configured to:

identify a storage resource map (SRM) for the plurality of SUs including the SUTBR; and

when the plurality of EDSs have been successfully transferred from the SUTBR to the RSU, update the SRM by replacing a first entry associated with the SUTBR with a second entry associated with the RSU.

4. The computing device of claim 1, wherein the processing module, when operable within the computing device based on the operational instructions, is further configured to:

direct the SUTBR to respond to a read request from another computing device for the at least one EDS of the plurality of EDSs by providing the at least one EDS of the plurality of EDSs stored within the SUTBR to the another computing device during transfer of the plurality of EDSs from the SUTBR to the RSU based on the first system configuration of the DAP.

5. The computing device of claim 1, wherein the processing module, when operable within the computing device based on the operational instructions, is further configured to:

direct the SUTBR to respond to a write request from another computing device to write the at least one EDS of the plurality of EDSs by storing the write request from the another computing device during transfer of the plurality of EDSs from the SUTBR to the RSU; and

direct the SUTBR to provide the write request that has been stored in the SUTBR from the SUTBR to the RSU when the plurality of EDSs have been successfully transferred from the SUTBR to the RSU for storage of the at least one EDS of the plurality of EDSs within the RSU based on the second system configuration of the DAP.

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

7. The computing device of claim 1 further comprising:

a SU of the plurality of SUs within the DSN.

8. The computing device of claim 1 further comprising:

a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

9. 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).

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

detecting a change from a first system configuration of a Decentralized, or Distributed, Agreement Protocol (DAP) to a second system configuration of the DAP based on a storage unit to be replaced (SUTBR) within a plurality of storage units (SUs) within a dispersed storage network (DSN), wherein the first system configuration of the DAP and the second system configuration of the DAP respectively provide for deterministic calculation of locations of encoded data slice (EDS) sets that correspond respectively to a plurality of data segments of a data object that are distributedly stored across the plurality of storage units (SUs) within the DSN, wherein the data object is segmented into the 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 a set of EDSs of the EDS sets that is of pillar width having a plurality of EDS names, wherein a read threshold number of EDSs of the set of EDSs provides for reconstruction of the data segment, wherein a write threshold number of EDSs of the set 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, wherein the data object is associated with a unique source name, and wherein each EDS name of the plurality of EDS names includes a reference to the unique source name;

directing the SUTBR to transfer a plurality of EDSs stored within the SUTBR to a replacement storage unit (RSU) for storage within the RSU;

during transfer of the plurality of EDSs from the SUTBR to the RSU;

directing the plurality of SUs to operate based on the first system configuration of the DAP; and

directing the SUTBR to service read requests and write requests from one or more other computing devices for at least one EDS of the plurality of EDSs based on the first system configuration of the DAP; and

when the plurality of EDSs have been successfully transferred from the SUTBR to the RSU;

directing the plurality of SUs to operate based on the second system configuration of the DAP; and

directing the RSU to service read and write requests from the one or more other computing devices for the at least one EDS of the plurality of EDSs based on the second system configuration of the DAP.

11. The method of claim 10, wherein:

the DAP, when executed using the unique source name and coefficients regarding the plurality of SUs of the DSN, produces a ranking of the plurality of SUs that deterministically identifies those SUs of the plurality of SUs that store the EDS sets including the set of EDSs of the EDS sets; and

further comprising;

updating the coefficients regarding the plurality of SUs based on the change from the first system configuration of the DAP to the second system configuration of the DAP.

12. The method of claim 10 further comprising:

identifying a storage resource map (SRM) for the plurality of SUs including the SUTBR; and

when the plurality of EDSs have been successfully transferred from the SUTBR to the RSU, updating the SRM by replacing a first entry associated with the SUTBR with a second entry associated with the RSU.

13. The method of claim 10 further comprising:

directing the SUTBR to respond to a read request from another computing device for the at least one EDS of the plurality of EDSs by providing the at least one EDS of the plurality of EDSs stored within the SUTBR to the another computing device during transfer of the plurality of EDSs from the SUTBR to the RSU based on the first system configuration of the DAP.

14. The method of claim 10 further comprising:

directing the SUTBR to respond to a write request from another computing device to write the at least one EDS of the plurality of EDSs by storing the write request from the another computing device during transfer of the plurality of EDSs from the SUTBR to the RSU; and

directing the SUTBR to provide the write request that has been stored in the SUTBR from the SUTBR to the RSU when the plurality of EDSs have been successfully transferred from the SUTBR to the RSU for storage of the at least one EDS of the plurality of EDSs within the RSU based on the second system configuration of the DAP.

15. The method of claim 10, wherein the computing device is located at a first premises that is remotely located from at least one SU of the plurality of SUs within the DSN.

16. The method of claim 10, wherein the computing device includes a SU of the plurality of SUs within the DSN.

17. The method of claim 10, wherein the computing device includes a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

18. The method of claim 10, 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).