Determining when to initiate an intra-distributed storage unit rebuild vs. an inter-distributed storage unit rebuild

• US 10,642,489 B2
• Filed: 12/11/2017
• Issued: 05/05/2020
• Est. Priority Date: 02/26/2013
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Pure Storage, Inc.
• Inventors: Kazi, Asimuddin, Resch, Jason K.
• Primary Examiner(s): Guyton, Philip
• Application Number:
  US15/837,536
• Publication Number:
  US 20180101305A1
• Time in Patent Office: 876 Days
• 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 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 11/3006 where the computing system is distributed, e.g. networked systems, clusters, multiprocessor systems multiprogramming arrangements G06F9/46; allocation of resources G06F9/50
• CPC Class Codes: G06F 11/3034 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 Class Codes: G06F 11/3055 Monitoring arrangements for monitoring the status of the computing system or of the computing system component, e.g. monitoring if the computing system is on, off, available, not available error or fault processing without redundancy G06F11/0703; error detection or correction by redundancy in data representation G06F11/08; error detection or correction by redundancy in operation G06F11/14; error detection or correction by redundancy in hardware G06F11/16
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 3/06 Digital input from, or digital output to, record carriers , e.g. RAID, emulated record carriers or networked record carriers
• CPC Class Codes: G06F 3/0604 Improving or facilitating administration, e.g. storage management
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0622 in relation to access
• CPC Class Codes: G06F 3/0629 Configuration or reconfiguration of storage systems
• 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]

Abstract

A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method begins by identifying an encoded data slice to be rebuilt within a DS unit, obtaining DS unit status information, selecting a rebuilding approach based on the DS unit status information, the rebuilding approach including an internal approach or an external approach. The method continues by obtaining, upon selecting the internal approach, internal rebuilding information from one or more memories of the DS unit and rebuilding the encoded data slice to be rebuilt utilizing the internal rebuilding information. The method continues by obtaining, upon selecting the external approach, external rebuilding information from at least a decode threshold number of other DS units of a set of DS units that includes the DS unit and rebuilding the encoded data slice to be rebuilt utilizing the external rebuilding information.

Claims

1. A method for execution by one or more processing modules of one or more computing devices of a distributed storage network (DSN), the method comprises:

identifying an encoded data slice to be rebuilt within a distributed storage (DS) unit;

obtaining status information of the DS unit;

selecting a rebuilding approach based on the status information, the rebuilding approach including an internal approach or an external approach, where the internal approach and the external approach are both available based on the status information;

obtaining, upon selecting the internal approach, internal rebuilding information from one or more memories of the DS unit, wherein the internal rebuilding information includes a decode threshold number of rebuilding elements; and

rebuilding the encoded data slice to be rebuilt utilizing the internal rebuilding information, wherein the threshold number of rebuilding elements includes at least a decode threshold number of internal memories of a plurality of internal memories within the DS unit;

obtaining, upon selecting the external approach, external rebuilding information from at least a decode threshold number of other DS units of a set of DS units that includes the DS unit; and

rebuilding the encoded data slice to be rebuilt utilizing the external rebuilding information.

2. The method of claim 1, wherein the identifying includes at least one of:

receiving an error message, comparing storage integrity information to calculated integrity information, or comparing a slice name list from the DS unit and from other DS units of a DS unit set that includes the DS unit.

3. The method of claim 1, wherein the status information includes one or more of:

a network traffic level, a number of available other DS units of the set of DS units, estimated network traffic costs, a loading level of the DS unit, available resources of the DS unit, or active operation types of the DS unit.

4. The method of claim 1, wherein the threshold number includes at least one of:

a threshold number of encoded data slices of a set of encoded data slices when a dispersed storage error coding function is utilized or a threshold number of data blocks or parity blocks when a redundant array of independent disks (RAID) function is utilized.

5. The method of claim 4, wherein the internal rebuilding information includes retrieving the threshold number of data blocks and parity blocks from a threshold number of the internal memories of the DS unit when the redundant array of independent disks (RAID) function is utilized.

6. The method of claim 1, wherein the internal rebuilding information further includes retrieving the threshold number of encoded data slices from a threshold number of the internal memories of the DS unit when a dispersed storage error coding function is utilized.

7. The method of claim 1, wherein the external approach includes utilizing the external rebuilding information for at least the threshold number of other DS units of the set of DS units, where data is encoded using a dispersed storage error coding function to produce a set of encoded data slices, including the encoded data slice to be rebuilt, that are stored in the set of DS units.

8. The method of claim 7, wherein the rebuilding includes decoding a retrieved threshold number of encoded data slices using a dispersed storage error coding function to produce a rebuilt slice.

9. The method of claim 1 further comprises determining a storage approach for the DS unit based on one or more of receiving the storage approach, a lookup, or selecting the storage approach based on storage requirements when initially storing data.

10. The method of claim 1, wherein the rebuilding the encoded data slice to be rebuilt utilizing the internal rebuilding information includes utilizing a RAID function on the threshold number of data blocks and parity blocks to produce the rebuilt encoded data slice.

11. The method of claim 1, wherein the obtain external rebuilding information includes issuing at least a decode threshold number of reads slice requests to other DS units and receiving at least a decode threshold number of read slice responses.

12. The method of claim 11, wherein the rebuildng the encoded data slice to be rebuilt utilizing the external rebuilding information includes decoding at least a decode threshold number of encoded data slices from the at least a decode threshold number of received read slice responses to produce the encoded data slice to be rebuilt.

13. A computing device of a group of computing devices of a distributed 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;

identify an encoded data slice to be rebuilt within a distributed storage (DS) unit;

obtain status information of the DS unit;

select a rebuilding approach based on the status information, the rebuilding approach including an internal approach or an external approach, where the internal approach and the external approach are both available based on the status information;

obtain, upon selecting the internal approach, internal rebuilding information from one or more memories of the DS unit, wherein the internal rebuilding information includes a threshold number of rebuilding elements; and

rebuild the encoded data slice to be rebuilt utilizing the internal rebuilding information wherein the threshold number of rebuilding elements includes at least a decode threshold number of internal memories of a plurality of internal memories within the DS unit;

obtain, upon selecting the external approach, external rebuilding information from at least a decode threshold number of other DS units of a set of DS units that includes the DS unit; and

rebuild the encoded data slice to be rebuilt utilizing the external rebuilding information.

14. The computing device of claim 13, wherein the status information includes one or more of:

a network traffic level, a number of available other DS units of the set of DS units, estimated network traffic costs, a loading level of the DS unit, available resources of the DS unit, or active operation types of the DS unit.

15. The computing device of claim 13, wherein the external approach includes utilizing the external rebuilding information for at least a threshold number of other DS units of the set of DS units, where data is encoded using a dispersed storage error coding function to produce a set of encoded data slices, including the encoded data slice to be rebuilt, that are stored in the set of DS units.

16. The computing device of claim 13, wherein the threshold number includes at least one of:

a threshold number of encoded data slices of a set of encoded data slices when a dispersed storage error coding function is utilized or a threshold number of data blocks and parity blocks when a redundant array of independent disks (RAID) function is utilized.

17. The computing device of claim 13, wherein the obtain external rebuilding information includes issuing at least a decode threshold number of reads slice requests to other DS units and receiving at least a decode threshold number of read slice responses.

18. A system 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;

identify an encoded data slice to be rebuilt within a distributed storage (DS) unit;

obtain status information of the DS unit;

select a rebuilding approach based on the status information, the rebuilding approach including an internal approach or an external approach, where the internal approach and the external approach are both available based on the status information;

obtain, upon selecting the internal approach, internal rebuilding information from one or more memories of the DS unit, wherein the internal rebuilding information includes a threshold number of rebuilding elements; and

rebuild the encoded data slice to be rebuilt utilizing the internal rebuilding information wherein the threshold number of rebuilding elements includes at least a decode threshold number of internal memories of a plurality of internal memories within the DS unit;

obtain, upon selecting the external approach, external rebuilding information from at least a decode threshold number of other DS units of a set of DS units that includes the DS unit; and

rebuild the encoded data slice to be rebuilt utilizing the external rebuilding information.