STRONG CONSISTENCY WRITE THRESHOLD

• US 20180101329A1
• Filed: 12/13/2017
• Published: 04/12/2018
• Est. Priority Date: 10/29/2014
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Gladwin, S. Christopher, Resch, Jason K.
• Granted Patent: US 10,282,135 B2
• Time in Patent Office: 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 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/064 Management of blocks
• CPC Class Codes: G06F 3/065 Replication mechanisms
• 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 9/5016 the resource being the memory
• 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 processing circuitry operably coupled to the interface and to the memory. The processing circuitry is configured to execute the operational instructions to perform various operations and functions.

The computing device operates based on a store data request from a requesting entity to dispersed error encode a data segment associated with a data object to generate a set of encoded data slices (EDSs). The computing device selects a write threshold number of EDSs based on a desired consistency level indicator and issues a write request to storage unit(s) (SU(s)). The computing device receives write response(s) from the SU(s) and, based on write response(s) received from the at least some of the SU(s), provides a store data response to the requesting entity.

Claims

1. A computing device comprising:

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

memory that stores operational instructions; and

processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to;

receive a store data request from a requesting entity;

dispersed error encode a data segment associated with a data object to generate a set of encoded data slices (EDSs), wherein the data object is segmented into a plurality of data segments, wherein the 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 to be distributedly stored among a plurality of storage units (SUs) that includes a first site including a first SU set and a first site including a second SU set;

select a write threshold number of EDSs based on a desired consistency level indicator, wherein the 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;

issue a write request to the plurality of SUs;

receive at least some write responses from at least some of the plurality of SUs;

determine whether a favorable number of write responses has been received from the at least some of the plurality of SUs; and

when fewer than the favorable number of write responses has been received from the at least some of the plurality of SUs;

issue at least one rollback request to at least one of the plurality of SUs; and

issue a store data response that indicates status of writing an EDS of the set of EDSs to a SU of the plurality of SUs to the requesting entity.

2. The computing device of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to:

when at least the favorable number of write responses has been received from the at least some of the plurality of SUs, issue another store data response that indicates status of successfully stored of at least one EDS of the set of EDSs to at least one SU of the plurality of SUs to the requesting entity.

3. The computing device of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to:

select the write threshold number of EDSs based on the desired consistency level indicator corresponding to a sum of a read threshold number of EDSs and the write threshold number of EDSs, wherein the read threshold number of EDSs provides for reconstruction of the data segment, wherein;

the set of EDSs is of pillar width and includes a pillar number of EDSs that is at least twice a decode threshold number of EDSs that are needed to recover the data segment;

the desired consistency level indicator corresponds to a strong consistency level when the sum is greater than or equal to the pillar number of EDSs; and

the desired consistency level indicator corresponds to a weak consistency level when the sum is less than the pillar number of EDSs.

4. The computing device of claim 1, wherein the processing circuitry is further configured to execute the operational instructions to:

select the write threshold number of EDSs based on at least one of the desired consistency level indicator, a system registry value, or storage unit (SU) performance levels associated with at least some of the plurality of SUs.

5. The computing device of claim 1, wherein at least one of:

the store data request includes at least one of the data object and the desired consistency level indicator;

the write request includes the set of EDSs;

or

a write response of the at least some write responses includes the status of writing an EDS of the set of EDSs to a SU of the plurality of SUs, wherein the status includes successfully stored or error.

6. The computing device of claim 1, wherein:

a decode threshold number of EDSs are needed to recover the data segment;

a read threshold number of EDSs provides for reconstruction of the data segment;

the set of EDSs is of pillar width and includes a pillar number of EDSs;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number.

7. The computing device of claim 1 further comprising:

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

8. 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).

9. A computing device comprising:

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

memory that stores operational instructions; and

processing circuitry operably coupled to the interface and to the memory, wherein the processing circuitry is configured to execute the operational instructions to;

receive a store data request from a requesting entity;

dispersed error encode a data segment associated with a data object to generate a set of encoded data slices (EDSs), wherein the data object is segmented into a plurality of data segments, wherein the 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 to be distributedly stored among a plurality of storage units (SUs) that includes a first site including a first SU set and a first site including a second SU set;

select a write threshold number of EDSs based on at least one of a desired consistency level indicator, a system registry value, or storage unit (SU) performance levels associated with at least some of the plurality of SUs, wherein the 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;

issue a write request to the plurality of SUs;

receive at least some write responses from at least some of the plurality of SUs;

determine whether a favorable number of write responses has been received from the at least some of the plurality of SUs; and

when fewer than the favorable number of write responses has been received from the at least some of the plurality of SUs;

issue at least one rollback request to at least one of the plurality of SUs; and

issue a store data response that indicates status of writing an EDS of the set of EDSs to a SU of the plurality of SUs to the requesting entity; and

when at least the favorable number of write responses has been received from the at least some of the plurality of SUs, issue another store data response that indicates status of successfully stored of at least one EDS of the set of EDSs to at least one SU of the plurality of SUs to the requesting entity.

10. The computing device of claim 9, wherein the processing circuitry is further configured to execute the operational instructions to:

select the write threshold number of EDSs based on the desired consistency level indicator corresponding to a sum of a read threshold number of EDSs and the write threshold number of EDSs, wherein the read threshold number of EDSs provides for reconstruction of the data segment, wherein;

the set of EDSs is of pillar width and includes a pillar number of EDSs that is at least twice a decode threshold number of EDSs that are needed to recover the data segment;

the desired consistency level indicator corresponds to a strong consistency level when the sum is greater than or equal to the pillar number of EDSs; and

the desired consistency level indicator corresponds to a weak consistency level when the sum is less than the pillar number of EDSs.

11. The computing device of claim 9, wherein at least one of:

the store data request includes at least one of the data object and the desired consistency level indicator;

the write request includes the set of EDSs;

or

a write response of the at least some write responses includes the status of writing an EDS of the set of EDSs to a SU of the plurality of SUs, wherein the status includes successfully stored or error.

12. The computing device of claim 9, wherein:

a decode threshold number of EDSs are needed to recover the data segment;

a read threshold number of EDSs provides for reconstruction of the data segment;

the set of EDSs is of pillar width and includes a pillar number of EDSs;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number.

13. The computing device of claim 9, wherein at least one of:

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

or

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).

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

receiving, via an interface of the computing device that is configured to interface and communicate with a dispersed or distributed storage network (DSN), a store data request from a requesting entity;

dispersed error encoding a data segment associated with a data object to generate a set of encoded data slices (EDSs), wherein the data object is segmented into a plurality of data segments, wherein the 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 to be distributedly stored among a plurality of storage units (SUs) that includes a first site including a first SU set and a first site including a second SU set;

selecting a write threshold number of EDSs based on a desired consistency level indicator, wherein the 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;

issuing, via the interface, a write request to the plurality of SUs;

receiving, via the interface, at least some write responses from at least some of the plurality of SUs;

determining whether a favorable number of write responses has been received from the at least some of the plurality of SUs; and

when fewer than the favorable number of write responses has been received from the at least some of the plurality of SUs;

issuing, via the interface, at least one rollback request to at least one of the plurality of SUs; and

issuing, via the interface, a store data response that indicates status of writing an EDS of the set of EDSs to a SU of the plurality of SUs to the requesting entity.

15. The method of claim 14 further comprising:

when at least the favorable number of write responses has been received from the at least some of the plurality of SUs, issuing, via the interface, another store data response that indicates status of successfully stored of at least one EDS of the set of EDSs to at least one SU of the plurality of SUs to the requesting entity.

16. The method of claim 14 further comprising:

selecting the write threshold number of EDSs based on the desired consistency level indicator corresponding to a sum of a read threshold number of EDSs and the write threshold number of EDSs, wherein the read threshold number of EDSs provides for reconstruction of the data segment, wherein;

the set of EDSs is of pillar width and includes a pillar number of EDSs that is at least twice a decode threshold number of EDSs that are needed to recover the data segment;

the desired consistency level indicator corresponds to a strong consistency level when the sum is greater than or equal to the pillar number of EDSs; and

the desired consistency level indicator corresponds to a weak consistency level when the sum is less than the pillar number of EDSs.

17. The method of claim 14 further comprising:

selecting the write threshold number of EDSs based on at least one of the desired consistency level indicator, a system registry value, or storage unit (SU) performance levels associated with at least some of the plurality of SUs.

18. The method of claim 14, wherein at least one of:

the store data request includes at least one of the data object and the desired consistency level indicator;

the write request includes the set of EDSs;

or

a write response of the at least some write responses includes the status of writing an EDS of the set of EDSs to a SU of the plurality of SUs, wherein the status includes successfully stored or error.

19. The method of claim 14, wherein:

a decode threshold number of EDSs are needed to recover the data segment;

a read threshold number of EDSs provides for reconstruction of the data segment;

the set of EDSs is of pillar width and includes a pillar number of EDSs;

each of the decode threshold number, the read threshold number, and the write threshold number is less than the pillar number; and

the write threshold number is greater than or equal to the read threshold number that is greater than or equal to the decode threshold number.

20. The method of claim 14, wherein at least one of:

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

or

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).