COORDINATING ARRIVAL TIMES OF DATA SLICES IN A DISPERSED STORAGE NETWORK

• US 20180107430A1
• Filed: 12/15/2017
• Published: 04/19/2018
• Est. Priority Date: 10/29/2014
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Resch, Jason K.
• Granted Patent: US 10,223,033 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 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

Methods for use in a dispersed storage network (DSN) to coordinate data slice arrival times. In various examples, a DSN computing device receives a store data request, the store data request including a data object. A set of storage units associated with the store data request is identified, and the data object is dispersed storage error encoded to produce a plurality of sets of encoded data slices. One or more sets of write slice requests that include one or more sets of encoded data slices are also generated for reception by storage units of the set of storage units. For each set of write slice requests, a transmission schedule is determined for each write slice request such that the set of write slice requests arrives at corresponding storage units at substantially the same time frame. Each of the write slice requests is then transmitted in accordance with the transmission schedule.

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 a store data request, the store data request including a data object;

identifying a set of storage units associated with the store data request;

dispersed storage error encoding the data object to produce a plurality of sets of encoded data slices, wherein the data object is segmented into a plurality of data segments and wherein each data segment is dispersed storage error encoded into a respective set of encoded data slices;

generating, for reception by storage units of the set of storage units, one or more sets of write slice requests that include one or more sets of encoded data slices;

determining, for each set of write slice requests, a transmission schedule for each write slice request such that the set of write slice requests arrives at corresponding storage units at substantially the same time frame; and

sending each write slice request in accordance with the transmission schedule.

2. The method of claim 1, wherein at least some of the storage units of the set of storage units are in differing locations, and wherein determining a transmission schedule comprises:

obtaining, for each storage unit of the set of storage units, a respective estimated transmission time for receiving a write slice request;

identifying a longest transmission time of the respective estimated transmission times; and

establishing, for each storage unit of the set of storage units, a time delay value as a difference between the longest transmission time and the respective estimated transmission time for a storage unit, wherein a time delay value indicates an amount of time to delay sending a corresponding write slice request after sending a write slice request to a storage unit associated with the longest transmission time.

3. The method of claim 2, wherein obtaining a respective estimated transmission time includes at least one of a lookup operation, initiating a test, or interpreting test results.

4. The method of claim 1 further comprises:

receiving write slice responses from at least some of the storage units of the set of storage units;

indicating successful storage of the one or more sets of encoded data slices when receiving a write threshold number of favorable write slice responses within a time frame; and

resending one or more write slice requests when not receiving the write threshold number of favorable write slice responses within the time frame.

5. The method of claim 4, wherein resending one or more write slice requests includes:

recalculating the transmission schedule to vary one or more delay times associated with the one or more write slice requests; and

resending the one or more write slice requests in accordance with the recalculated transmission schedule.

6. The method of claim 1, wherein identifying the set of storage units includes at least one of interpreting a vault lookup based on a requester identifier, performing a random selection, performing a selection based on available storage capacity, performing a selection based on performance, or performing a selection based on transmission time delays to each storage unit of the set of storage units.

7. The method of claim 1, wherein generating one or more sets of write slice requests further includes:

generating a plurality of slice names corresponding to the one or more sets of encoded data slices, wherein each write slice request of the one or more sets of write slice requests further includes a slice name corresponding to a respective encoded data slice of the write slice request.

8. The method of claim 1, wherein the store data request further includes a requester identifier and a data object name.

9. A computer readable storage medium comprises:

at least one memory section that stores operational instructions that, when executed by one or more processing modules of a dispersed storage network (DSN) that include a processor and a memory, causes the one or more processing modules to;

receive a store data request, the store data request including a data object;

identify a set of storage units associated with the store data request;

dispersed storage error encode the data object to produce a plurality of sets of encoded data slices, wherein the data object is segmented into a plurality of data segments and wherein each data segment is dispersed storage error encoded into a respective set of encoded data slices;

generate, for reception by storage units of the set of storage units, one or more sets of write slice requests that include one or more sets of encoded data slices;

determine, for each set of write slice requests, a transmission schedule for each write slice request such that the set of write slice requests arrives at corresponding storage units at substantially the same time frame; and

send each write slice request in accordance with the transmission schedule.

10. The computer readable storage medium of claim 9, wherein the at least one memory section stores further operational instructions that, when executed by the one or more processing modules to determine a transmission schedule, causes the one or more processing modules to:

obtain, for each storage unit of the set of storage units, a respective estimated transmission time for receiving a write slice request;

identify a longest transmission time of the respective estimated transmission times; and

establish, for each storage unit of the set of storage units, a time delay value as a difference between the longest transmission time and the respective estimated transmission time for a storage unit, wherein a time delay value indicates an amount of time to delay sending a corresponding write slice request after sending a write slice request to a storage unit associated with the longest transmission time.

11. The computer readable storage medium of claim 10, wherein obtaining a respective estimated transmission time includes at least one of a lookup operation, initiating a test, or interpreting test results.

12. The computer readable storage medium of claim 9, wherein the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more processing modules to:

receive write slice responses from at least some of the storage units of the set of storage units;

indicate successful storage of the one or more sets of encoded data slices when receiving a write threshold number of favorable write slice responses within a time frame; and

resend one or more write slice requests when not receiving the write threshold number of favorable write slice responses within the time frame.

13. The computer readable storage medium of claim 12, wherein the at least one memory section stores further operational instructions that, when executed by the one or more processing modules to resend one or more write slice requests, causes the one or more processing modules to:

recalculate the transmission schedule to vary one or more delay times associated with the one or more write slice requests; and

resend the one or more write slice requests in accordance with the recalculated transmission schedule.

14. The computer readable storage medium of claim 9, wherein identifying the set of storage units includes at least one of interpreting a vault lookup based on a requester identifier, performing a random selection, performing a selection based on available storage capacity, performing a selection based on performance, or performing a selection based on transmission time delays to each storage unit of the set of storage units.

15. A computing device of a dispersed storage network (DSN), the computing device comprises:

a network interface;

a memory comprising instructions; and

one or more processing modules in communication with the memory, wherein the one or more processing modules execute the instructions to;

receive, via the network interface, a store data request, the store data request including a data object;

identify a set of storage units associated with the store data request;

dispersed storage error encode the data object to produce a plurality of sets of encoded data slices, wherein the data object is segmented into a plurality of data segments and wherein each data segment is dispersed storage error encoded into a respective set of encoded data slices;

generate, for reception by storage units of the set of storage units, one or more sets of write slice requests that include one or more sets of encoded data slices;

determine, for each set of write slice requests, a transmission schedule for each write slice request such that the set of write slice requests arrives at corresponding storage units at substantially the same time frame; and

send, via the network interface, each write slice request in accordance with the transmission schedule.

16. The computing device of claim 15, wherein the one or more processing modules further execute the instructions to:

obtain, for each storage unit of the set of storage units, a respective estimated transmission time for receiving a write slice request;

identify a longest transmission time of the respective estimated transmission times; and

when determining the transmission schedule, establish, for each storage unit of the set of storage units, a time delay value as a difference between the longest transmission time and the respective estimated transmission time for a storage unit, wherein a time delay value indicates an amount of time to delay sending a corresponding write slice request after sending a write slice request to a storage unit associated with the longest transmission time.

17. The computing device of claim 16, wherein obtaining a respective estimated transmission time includes at least one of a lookup operation, initiating a test, or interpreting test results.

18. The computing device of claim 15, wherein the one or more processing modules further execute the instructions to:

receive, via the network interface, write slice responses from at least some of the storage units of the set of storage units;

indicate successful storage of the one or more sets of encoded data slices when receiving a write threshold number of favorable write slice responses within a time frame; and

resend one or more write slice requests when not receiving the write threshold number of favorable write slice responses within the time frame.

19. The computing device of claim 18, wherein resending one or more write slice requests includes:

recalculating the transmission schedule to vary one or more delay times associated with the one or more write slice requests; and

resending the one or more write slice requests in accordance with the recalculated transmission schedule.

20. The computing device of claim 15, wherein identifying the set of storage units includes at least one of interpreting a vault lookup based on a requester identifier, performing a random selection, performing a selection based on available storage capacity, performing a selection based on performance, or performing a selection based on transmission time delays to each storage unit of the set of storage units.