Proactively deselect storage units for access during major geographic events

• US 10,216,443 B2
• Filed: 11/01/2016
• Issued: 02/26/2019
• Est. Priority Date: 11/30/2015
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Hegde, Harsha
• Primary Examiner(s): Dorman, Christian M
• Application Number:
  US15/340,017
• Publication Number:
  US 20170153828A1
• Time in Patent Office: 847 Days
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units 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 Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 16/258 Data format conversion from or to a database
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0631 by allocating resources to storage systems
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• 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: H03M 13/616 Matrix operations, especially for generator matrices or check matrices, e.g. column or row permutations
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• 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 67/565 Conversion or adaptation of application format or content adding application control or application functional data H04L67/561

Abstract

A method for execution by one or more processing modules of a dispersed storage network (DSN), the method begins when accessing a multi-site DSN, by determining, for each site, whether the site is able to favorably support slice access. Unfavorable conditions include any of: weather-related site availability information that is greater than a weather threshold level, seismic activity at the site is greater than a seismic threshold level, general environmental conditions at the site are unfavorable, building fire conditions, unauthorized site physical access conditions, power supply conditions, or network connectivity conditions. The method continues, for each site that is able to favorably support slice access, by selecting one or more storage units to support the accessing. The method continues by issuing access requests to the selected one or more storage units and receiving access responses from at least a threshold number of the selected one or more storage units.

Claims

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:

receiving warnings indicating a major geographic event occurring at a DSN site;

when accessing a multi-site DSN, determining, for each DSN site, whether the DSN site is able to favorably support encoded data slice access based on site availability information, wherein the site availability is based on whether the DSN site is experiencing or expects to experience the major geographic event, and wherein encoded data slices are dispersed in a plurality of the DSN sites in a threshold number of storage units using a data segmenting protocol with per data segment encoding values including;

a pillar width, number (T) of encoded data slices per encoding of a data segment;

a decode threshold number (D) of encoded data slices of a set of encoded data slices that are needed to recover the data segment;

a read threshold number (R) of encoded data slices to indicate a number of encoded data slices per set to be read from storage for decoding of the data segment; and

a write threshold number (W) to indicate a number of encoded data slices per set that must be accurately stored before the encoded data slices are deemed to have been properly stored;

for each DSN site that cannot favorably support encoded data slice access based on the site availability and access responses from at least a threshold number of storage units, wherein the threshold number includes any of D, R or W;

pausing read and writes to the DSN site proactively;

transferring the paused read and writes to other non-impacted DSN sites; and

returning failures to requesters requesting access to the DSN site with appropriate reason codes;

for each non-impacted DSN site that is able to favorably support encoded data slice access and the threshold number (D, R or W) of storage units, selecting one or more storage units to support the accessing;

issuing access requests to the selected one or more storage units; and

receiving access responses from at least the threshold number (D, R or W) of the selected one or more storage units.

2. The method of claim 1, wherein the determining includes any of:

obtaining centralized site availability information, obtaining the site availability information from a site availability unit of the DSN site, interpreting a query response, interpreting a test result, or indicating favorable support of the encoded data slice access based on the site availability information.

3. The method of claim 2, wherein the site availability information includes unavailability when weather-related site information is greater than a weather threshold level.

4. The method of claim 2, wherein the site availability information includes unavailability when seismic activity at the DSN site is greater than a seismic threshold level.

5. The method of claim 2, wherein the site availability information includes unavailability when general environmental conditions at the DSN site are unfavorable.

6. The method of claim 2, wherein the site availability information includes unavailability based on site specific building fire conditions, unauthorized site physical access conditions, power supply conditions, or network connectivity conditions.

7. The method of claim 1, wherein the selecting is based on one or more of:

the site availability information, storage unit availability information, storage unit performance information, storage unit capacity information, or dispersal parameters.

8. The method of claim 1, wherein the issuing is based on:

generating an access request, and sending, via a network, the access request to the selected one or more storage units.

9. The method of claim 8, wherein the receiving is based on:

when the site availability information is favorable, generating, by the selected one or more storage units receiving a corresponding one of the access requests, a corresponding one of the access responses, and sending, via a network, the access response.

10. 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;

receive warnings indicating a major geographic event is occurring at a DSN site;

when accessing a multi-site DSN, determine, for each DSN site, whether the DSN site is able to favorably support encoded data slice access based on site availability information, wherein the site availability is based on whether the DSN site is experiencing or expects to experience the major geographic event, and wherein encoded data slices are dispersed in a plurality of the DSN sites in a threshold number of storage units using a data segmenting protocol with per data segment encoding values including;

a pillar width, number (T) of encoded data slices per encoding of a data segment;

a decode threshold number (D) of encoded data slices of a set of encoded data slices that are needed to recover the data segment;

a read threshold number (R) of encoded data slices to indicate a number of encoded data slices per set to be read from storage for decoding of the data segment; and

a write threshold number (W) to indicate a number of encoded data slices per set that must be accurately stored before the encoded data slices are deemed to have been properly stored;

for each DSN site that cannot favorably support encoded data slice access based on the site availability and access responses from at least a threshold number of storage units, wherein the threshold number includes any of D, R or W;

pause read and writes to the DSN site proactively;

transfer the paused read and writes to other non-impacted DSN sites; and

return failures to requesters requesting access to the DSN site with appropriate reason codes;

for each non-impacted DSN site that is able to favorably support encoded data slice access and the threshold number (D, R or W) of storage units, select one or more storage units to support the accessing;

issue access requests to the selected one or more storage units; and

received access responses from at least the threshold number (D, R or W) of the selected one or more storage units.

11. The computing device of claim 10, wherein the determining includes any of:

obtaining centralized site availability information, obtaining the site availability information from a site availability unit of the DSN site, interpreting a query response, interpreting a test result, or indicating favorable support of the encoded data slice access based on the site availability information.

12. The computing device of claim 11, wherein the site availability information includes unavailability when weather-related site information is greater than a weather threshold level.

13. The computing device of claim 11, wherein the site availability information includes unavailability when seismic activity at the DSN site is greater than a seismic threshold level.

14. The computing device of claim 11, wherein the site availability information includes unavailability when based on any of:

site specific building fire conditions, unauthorized site physical access conditions, power supply conditions, or network connectivity conditions.

15. The computing device of claim 10, wherein the selecting is based on one or more of:

the site availability information, storage unit availability information, storage unit performance information, storage unit capacity information, or dispersal parameters.

16. The computing device of claim 10, wherein the issuing is based on:

generating an access request, and sending, via a network, the access request to the selected one or more storage units.

17. The computing device of claim 16, wherein the receiving is based on:

when site availability information is favorable, generating, by the selected one or more storage units receiving a corresponding one of the access requests, a corresponding one of the access responses, and sending, via a network, the access response.

18. 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 site availability unit providing site availability information of a DSN site; and

a processing module operably coupled to the interface, the local memory and the site availability unit, wherein the processing module functions to;

receive warnings indicating a major geographic event is occurring at a DSN site;

when receiving a request for accessing a plurality of sites of a multi-site DSN, determine based on the site availability information of each of the plurality of sites, whether the DSN site is able to favorably support encoded data slice access, wherein the site availability is based on whether the DSN site is experiencing or expects to experience the major geographic event, and wherein encoded data slices are dispersed in a plurality of the DSN sites in a threshold number of storage units using a data segmenting protocol with per data segment encoding values including;

a pillar width, number (T) of encoded data slices per encoding of a data segment;

a decode threshold number (D) of encoded data slices of a set of encoded data slices that are needed to recover the data segment;

a read threshold number (R) of encoded data slices to indicate a number of encoded data slices per set to be read from storage for decoding of the data segment and a write threshold number (W) to indicate a number of encoded data slices per set that must be accurately stored before the encoded data slices are deemed to have been properly stored;

for each DSN site that cannot favorably support encoded data slice access based on the site availability and access responses from at least a threshold number of storage units, wherein the threshold number includes any of D, R or W;

pause read and writes to the DSN site proactively;

transfer the paused read and writes to other non-impacted DSN sites; and

return failures to requesters requesting access to the DSN site with appropriate reason codes;

for each non-impacted DSN site that is able to favorably support encoded data slice access and the threshold number (D, R or W) of storage units, select one or more storage units to support the accessing;

issue access requests to the selected one or more storage units; and

received access responses from at least the threshold number (D, R or W) of the selected one or more storage units.

19. The computing device of claim 18, wherein the determining includes any of:

obtaining centralized site availability information, obtaining the site availability information from the site availability unit of the DSN site, interpreting a query response, interpreting a test result, or indicating favorable support of the encoded data slice access based on the site availability information.

20. The computing device of claim 18, wherein the site availability information includes unavailability when any of:

weather-related site availability information is greater than a weather threshold level, seismic activity at the DSN site is greater than a seismic threshold level, general environmental conditions at the DSN site are unfavorable, building fire conditions, unauthorized DSN site physical access conditions, power supply conditions, or network connectivity conditions.