Optimistic checked writes

• US 10,044,807 B2
• Filed: 12/12/2017
• Issued: 08/07/2018
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Dhuse, Greg R.
• Primary Examiner(s): Bradley, Matthew
• Application Number:
  US15/839,457
• Publication Number:
  US 20180103105A1
• Time in Patent Office: 238 Days
• Field of Search: 711103
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• 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 67/306 User profiles

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 dispersed error encodes a data segment to produce a set of encoded data slices (EDSs) and selects a subset of a set of storage units (SUs). Then, the computing device transmits list slice requests to the subset of the set of SUs and receive list slice responses from at least some of them. The computing device determines a highest current revision level based on list slice responses and select a revision level for the set of EDSs. The computing device generates a set of checked revision slice requests and transmit them to the set of SUs.

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;

dispersed error encode a data segment associated with a data object to produce 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, wherein the set of EDSs to be distributedly stored among a plurality of storage units (SUs) within the DSN;

select a subset of a set of SUs, wherein the subset of the set of SUs having a most favorable reliability level among the set of SUs;

transmit list slice requests to the subset of the set of SUs;

receive list slice responses from at least some of the set of SUs;

determine a highest current revision level based on list slice responses;

select a revision level for the set of EDSs;

generate a set of checked revision slice requests that includes the highest current revision level based on list slice responses and the revision level for the set of EDSs; and

transmit the set of checked revision slice requests to the set of SUs.

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

generate the list slice requests to include slice names associated with corresponding EDSs of the set of EDS; and

transmit the list slice requests to the subset of the set of SUs.

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

extract revision levels from the list slice responses; and

determine the highest current revision level of the set of EDSs in accordance with an approach that is based on at least one of a predetermination, a historical storage reliability level, a performance goal, selecting the highest revision level, selecting a common highest revision level, or selecting a majority highest revision level.

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

select the revision level for the set of EDSs to be greater than the highest current revision level when storing new data.

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

generate a checked revision write slice request of the set of checked revision slice requests to include at least one of a transaction number, an EDS of the set of EDSs a slice name associated with the EDS of the set of EDSs, the highest current revision level, or the revision level.

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;

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;

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 set of SUs or another set 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;

dispersed error encode a data segment associated with a data object to produce 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, wherein the set of EDSs to be distributedly stored among a plurality of storage units (SUs) within the DSN;

select a subset of a set of SUs, wherein the subset of the set of SUs having a most favorable reliability level among the set of SUs;

generate list slice requests to include slice names associated with corresponding EDSs of the set of EDS;

transmit the list slice requests to the subset of the set of SUs;

receive list slice responses from at least some of the set of SUs;

determine a highest current revision level based on list slice responses;

select a revision level for the set of EDSs;

generate a set of checked revision slice requests that includes the highest current revision level based on list slice responses and the revision level for the set of EDSs including to generate a checked revision write slice request of the set of checked revision slice requests to include at least one of a transaction number, an EDS of the set of EDSs a slice name associated with the EDS of the set of EDSs, the highest current revision level, or the revision level; and

transmit the set of checked revision slice requests to the set of SUs.

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

extract revision levels from the list slice responses;

determine the highest current revision level of the set of EDSs in accordance with an approach that is based on at least one of a predetermination, a historical storage reliability level, a performance goal, selecting the highest revision level, selecting a common highest revision level, or selecting a majority highest revision level; and

select the revision level for the set of EDSs to be greater than the highest current revision level when storing new data.

11. 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;

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;

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.

12. The computing device of claim 9 further comprising:

a SU of the set of SUs or another set 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.

13. The computing device of claim 9, 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).

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

dispersed error encoding a data segment associated with a data object to produce 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, wherein the set of EDSs to be distributedly stored among a plurality of storage units (SUs) within the dispersed or distributed storage network (DSN);

selecting a subset of a set of SUs, wherein the subset of the set of SUs having a most favorable reliability level among the set of SUs;

transmitting, via an interface of the computing device that is configured to interface and communicate with the DSN, list slice requests to the subset of the set of SUs;

receiving, via the interface, list slice responses from at least some of the set of SUs;

determining a highest current revision level based on list slice responses;

selecting a revision level for the set of EDSs;

generating a set of checked revision slice requests that includes the highest current revision level based on list slice responses and the revision level for the set of EDSs; and

transmitting, via the interface, the set of checked revision slice requests to the set of SUs.

15. The method of claim 14 further comprising:

generating the list slice requests to include slice names associated with corresponding EDSs of the set of EDS; and

transmitting, via the interface, the list slice requests to the subset of the set of SUs.

16. The method of claim 14 further comprising:

extracting revision levels from the list slice responses; and

determining the highest current revision level of the set of EDSs in accordance with an approach that is based on at least one of a predetermination, a historical storage reliability level, a performance goal, selecting the highest revision level, selecting a common highest revision level, or selecting a majority highest revision level.

17. The method of claim 14 further comprising:

selecting the revision level for the set of EDSs to be greater than the highest current revision level when storing new data.

18. The method of claim 14 further comprising:

generating a checked revision write slice request of the set of checked revision slice requests to include at least one of a transaction number, an EDS of the set of EDSs a slice name associated with the EDS of the set of EDSs, the highest current revision level, or the revision level.

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;

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;

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 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).