Intelligent read strategy within a dispersed storage network (DSN)

• US 10,042,566 B2
• Filed: 08/26/2016
• Issued: 08/07/2018
• Est. Priority Date: 08/31/2015
• Status: Expired due to Fees

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Resch, Jason K.
• Primary Examiner(s): Chaudry, Mujtaba M
• Application Number:
  US15/249,187
• Publication Number:
  US 20170060686A1
• Time in Patent Office: 711 Days
• Field of Search: None
• 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 11/3034 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 11/3409 for performance assessment
• CPC Class Codes: G06F 12/1408 by using cryptography for digital transmission H04L9/00
• CPC Class Codes: G06F 2212/1052 Security improvement
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0622 in relation to access
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0637 Permissions
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/0644 Management of space entities, e.g. partitions, extents, pools
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• 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 computing device includes an interface configured to interface and communicate with a dispersed storage network (DSN), a memory that stores operational instructions, and a processing module operably coupled to the interface and memory such that the processing module, when operable within the computing device based on the operational instructions, is configured to perform various operations. For example, the computing device generates and transmits a read request for a set of encoded data slices (EDSs) of a data object to primary storage units (SUs). The data object is stored within primary and secondary SUs. The computing device then receives at least the read threshold number of EDSs from the plurality of primary SUs. The primary SUs operate selectively to provide the at least the read threshold number of EDSs to the computing device either from memory of primary SU(s) or from secondary SU(s).

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;

generate a read request for a set of encoded data slices (EDSs) of a data object that is distributedly stored within a plurality of primary storage units (SUs) and a plurality of secondary SUs within the DSN, wherein the read request includes a read extra request that specifies at least one of more than a read threshold number of EDSs from the plurality of primary SUs or instruction to a SU of the plurality of primary SUs to forward the read request to at least one SU of the plurality of secondary SUs when a DSN operational characteristic compares unfavorably to an acceptable DSN operational characteristic as determined by the computing device, wherein sets of EDSs of the data object are distributedly stored within the plurality of primary SUs and the plurality of secondary SUs within the DSN, wherein the data object is segmented into a 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 the set of EDSs that is of pillar width, wherein a decode threshold number of EDSs are needed to recover the data segment, wherein the read threshold number of EDSs provides for reconstruction of the data segment, wherein a write threshold number 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;

transmit via the interface and via the DSN the read request for the set of EDSs of the data object to the plurality of primary SUs within the DSN; and

receive via the interface and via the DSN at least the read threshold number of EDSs from the plurality of primary SUs, wherein;

the SU of the plurality of primary SUs provides an EDS of the set of EDSs from memory of the SU of the plurality of primary SUs to the computing device via the DSN and via the interface when the EDS of the set of EDSs is stored and available within the SU of the plurality of primary SUs; and

the SU of the plurality of primary SUs provides the EDS of the set of EDSs to the computing device via the DSN and via the interface after receipt thereof from a SU of the plurality of secondary SUs when at least one of the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the SU of the plurality of primary SUs or the EDS of the set of EDSs is unavailable within the memory of the SU of the plurality of primary SUs.

2. 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 the plurality of primary SUs among a plurality of overall SUs of the DSN based on an affinity of the plurality of primary SUs that specifies an estimated likelihood that the set of EDSs are stored within the plurality of primary SUs.

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:

generate the read request for the set of EDSs of the data object to specify instruction for the SU of the plurality of primary SUs to generate another read extra request that specifies the more than the read threshold number of EDSs based on the read request forwarded from the SU of the plurality of primary SUs and to transmit the another read extra request to the at least one SU of the plurality of secondary SUs.

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:

generate the read request for the set of EDSs of the data object that is stored within the plurality of primary SUs and the plurality of secondary SUs within the DSN, wherein the read request specifies no more than the read threshold number of EDSs when the DSN operational characteristic compares favorably to the acceptable DSN operational characteristic as determined by the computing device; and

receive the read threshold number of EDSs from the plurality of primary SUs in response to the plurality of primary SUs.

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:

instruct at least one SU of the plurality of primary SUs to generate at least one redundant EDS based on at least one EDS of the set of EDSs and to transmit the at least one redundant EDS to the at least one SU of the plurality of secondary SUs for storage therein when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device.

6. 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:

instruct at least one SU of the plurality of primary SUs to generate a copy of the set of EDSs and to transmit the copy of the set of EDSs to the plurality of secondary SUs for storage therein when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device.

7. The computing device of claim 1, wherein:

the read extra request specifies a first number of EDSs that is more than the read threshold number of EDSs from the plurality of primary SUs when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device within a first unfavorable comparison range; and

the read extra request specifies a second number of EDSs that is more than the read threshold number of EDSs from the plurality of primary SUs when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device within a second unfavorable comparison range.

8. 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 primary SUs or plurality of secondary SUs the within the DSN.

9. The computing device of claim 1 further comprising:

a SU of the plurality of primary SUs or the plurality of secondary SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

10. 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).

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

generating a read request for a set of encoded data slices (EDSs) of a data object that is distributedly stored within a plurality of primary storage units (SUs) and a plurality of secondary SUs within a dispersed storage network (DSN), wherein the read request includes a read extra request that specifies at least one of more than a read threshold number of EDSs from the plurality of primary SUs or instruction to a SU of the plurality of primary SUs to forward the read request to at least one SU of the plurality of secondary SUs when a DSN operational characteristic compares unfavorably to an acceptable DSN operational characteristic as determined by the computing device, wherein sets of EDSs of the data object are distributedly stored within the plurality of primary SUs and the plurality of secondary SUs within the DSN, wherein the data object is segmented into a 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 the set of EDSs that is of pillar width, wherein a decode threshold number of EDSs are needed to recover the data segment, wherein the read threshold number of EDSs provides for reconstruction of the data segment, wherein a write threshold number 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;

transmitting, via an interface of the computing device configured to interface and communicate with the DSN and via the DSN, the read request for the set of EDSs of the data object to the plurality of primary SUs within the DSN; and

receiving, via the interface of the computing device configured to interface and communicate with the DSN and via the DSN, at least the read threshold number of EDSs from the plurality of primary SUs, wherein;

the SU of the plurality of primary SUs provides an EDS of the set of EDSs from memory of the SU of the plurality of primary SUs to the computing device via the DSN and via the interface when the EDS of the set of EDSs is stored and available within the SU of the plurality of primary SUs; and

the SU of the plurality of primary SUs provides the EDS of the set of EDSs to the computing device via the DSN and via the interface after receipt thereof from a SU of the plurality of secondary SUs when at least one of the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the SU of the plurality of primary SUs or the EDS of the set of EDSs is unavailable within the memory of the SU of the plurality of primary SUs.

12. The method of claim 11 further comprising:

identifying the plurality of primary SUs among a plurality of overall SUs of the DSN based on an affinity of the plurality of primary SUs that specifies an estimated likelihood that the set of EDSs are stored within the plurality of primary SUs.

13. The method of claim 11 further comprising:

generating the read request for the set of EDSs of the data object to specify instruction for the SU of the plurality of primary SUs to generate another read extra request that specifies the more than the read threshold number of EDSs based on the read request forwarded from the SU of the plurality of primary SUs and to transmit the another read extra request to the at least one SU of the plurality of secondary SUs.

14. The method of claim 11 further comprising:

generating the read request for the set of EDSs of the data object that is stored within the plurality of primary SUs and the plurality of secondary SUs within the DSN, wherein the read request specifies no more than the read threshold number of EDSs when the DSN operational characteristic compares favorably to the acceptable DSN operational characteristic as determined by the computing device; and

receiving, via the interface of the computing device configured to interface and communicate with the DSN, the read threshold number of EDSs from the plurality of primary SUs in response to the plurality of primary SUs.

15. The method of claim 11 further comprising:

instructing at least one SU of the plurality of primary SUs to generate at least one redundant EDS based on at least one EDS of the set of EDSs and to transmit the at least one redundant EDS to the at least one SU of the plurality of secondary SUs for storage therein when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device.

16. The method of claim 11 further comprising:

instructing at least one SU of the plurality of primary SUs to generate a copy of the set of EDSs and to transmit the copy of the set of EDSs to the plurality of secondary SUs for storage therein when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device.

17. The method of claim 11, wherein:

the read extra request specifies a first number of EDSs that is more than the read threshold number of EDSs from the plurality of primary SUs when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device within a first unfavorable comparison range; and

the read extra request specifies a second number of EDSs that is more than the read threshold number of EDSs from the plurality of primary SUs when the DSN operational characteristic compares unfavorably to the acceptable DSN operational characteristic as determined by the computing device within a second unfavorable comparison range.

18. The method of claim 11, wherein the computing device is located at a first premises that is remotely located from at least one SU of the plurality of primary SUs of the plurality of secondary SUs within the DSN.

19. The method of claim 11, wherein the computing device is a SU of the plurality of primary SUs of the plurality of secondary SUs within the DSN, a wireless smart phone, a laptop, a tablet, a personal computers (PC), a work station, or a video game device.

20. The method of claim 11, 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).