Storing data in a dispersed storage network

• US 9,652,470 B2
• Filed: 06/17/2014
• Issued: 05/16/2017
• Est. Priority Date: 07/01/2013
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Volvovski, Ilya, Khadiwala, Ravi, Dhuse, Greg, Resch, Jason K.
• Primary Examiner(s): Tran, Anh Tai
• Application Number:
  US14/306,335
• Publication Number:
  US 20150006594A1
• Time in Patent Office: 1,064 Days
• Field of Search: None
• CPC Class Codes: G06F 11/10 Adding special bits or symbols to the coded information, e.g. parity check, casting out 9's or 11's
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 16/2379 Updates performed during online database operations; commit processing
• 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 3/0659 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]
• 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 method begins by a dispersed storage (DS) processing module transmitting a set of write commands for storing a set of encoded data slices in storage units of a dispersed storage network (DSN) and determining whether at least a first threshold number of write responses have been received within a response time period. When the at least the first threshold number of the write responses have been received within the response time period, the method continues with the DS processing module determining whether a total number of responses have been received within another response time period. When the total number of responses have not been received within the other response time period, the method continues with the DS processing module issuing a sub-set of write commit commands corresponding to a response number of encoded data slices for which a response was received.

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:

transmitting a set of write commands for storing a set of encoded data slices in storage units of the DSN, wherein a data segment is dispersed storage error encoded into the set of encoded data slices, wherein the set of encoded data slices includes a total number of encoded data slices, wherein a threshold number of encoded data slices is needed to recover the data segment, and wherein the threshold number is less than the total number;

determining whether at least a first threshold number of write responses have been received within a first response time period;

when the at least the first threshold number of the write responses have been received within the first response time period and the at least the first threshold number is less than the total number, determining whether at least a second threshold number of the write responses have been received within a second response time period, wherein the first threshold number is less than the second threshold number and wherein the second response time period is subsequent to the first response time period;

when the at least the second threshold number of the write responses have been received within the second response time period and the at least the second threshold number is less than the total number, determining whether a total number of write responses have been received within a third response time period, wherein the second threshold number is less than the total number and wherein the third response time period is subsequent to the second response time period; and

when the total number of write responses have not been received within the third response time period, issuing a sub-set of write commit commands corresponding to a response number of encoded data slices for which a write response was received, wherein the response number is less than the total number and is equal to or greater than the at least the second threshold number.

2. The method of claim 1 further comprises:

when the at least the first threshold number of the write responses have not been received within the first response time period, indicating a write failure.

3. The method of claim 1 further comprises:

when the at least the first threshold number of the write responses have been received within the first response time period and the at least the first threshold number is equal to the total number, issuing a set of write commit commands corresponding to the set of encoded data slices.

4. The method of claim 1 further comprises:

when the at least the second threshold number of the write responses have not been received within the second response time period, issuing a second sub-set of write commit commands corresponding to a second response number of encoded data slices for which the write response was received prior to expiration of the second response time period.

5. The method of claim 1 further comprises:

when the at least the second threshold number of the write responses have been received within the second response time period and the at least the second threshold number is equal to the total number, issuing a set of write commit commands corresponding to the set of encoded data slices.

6. The method of claim 1 further comprises:

when the total number of write responses have been received within the third response time period, issuing a set of write commit commands corresponding to the set of encoded data slices.

7. The method of claim 1 further comprises:

prior to expiration of the third response time period, determining whether at least a fourth threshold number of write responses have been received within a fourth response time period, wherein the fourth threshold number is less than the total number and wherein the fourth response time period is a portion of the third response time period and is subsequent to the second response time period; and

when the at least the fourth threshold number of the write responses have been received within the fourth response time period and the at least the fourth threshold number is less than the total number, determining whether the total number of write responses have been received within the third response time period.

8. The method of claim 1 further comprises:

pre-establishing the first, second, and third response time periods.

9. The method of claim 1 further comprises:

determining the second response time period based on the first response time period and the receiving of the at least the first threshold number of write responses; and

determining the third response time period based on the receiving of the at least the second threshold number of write responses.

10. A dispersed storage (DS) module of a dispersed storage network (DSN), the DS module comprises:

a first module, when operable within a computing device, causes the computing device to;

transmit a set of write commands for storing a set of encoded data slices in storage units of the DSN, wherein a data segment is dispersed storage error encoded into the set of encoded data slices, wherein the set of encoded data slices includes a total number of encoded data slices, wherein a threshold number of encoded data slices is needed to recover the data segment, and wherein the threshold number is less than the total number;

a second module, when operable within the computing device, causes the computing device to;

determine whether at least a first threshold number of write responses have been received within a first response time period;

a third module, when operable within the computing device, causes the computing device to;

when the at least the first threshold number of the write responses have been received within the first response time period and the at least the first threshold number is less than the total number, determine whether at least a second threshold number of the write responses have been received within a second response time period, wherein the first threshold number is less than the second threshold number and wherein the second response time period is subsequent to the first response time period;

a fourth module, when operable within the computing device, causes the computing device to;

when the at least the second threshold number of the write responses have been received within the second response time period and the at least the second threshold number is less than the total number, determine whether a total number of write responses have been received within a third response time period, wherein the second threshold number is less than the total number and wherein the third response time period is subsequent to the second response time period; and

a fifth module, when operable within the computing device, causes the computing device to;

when the total number of write responses have not been received within the third response time period, issue a sub-set of write commit commands corresponding to a response number of encoded data slices for which a write response was received, wherein the response number is less than the total number and is equal to or greater than the at least the second threshold number.

11. The DS module of claim 10 further comprises:

the second module, when operable within the computing device, further causes the computing device to;

when the at least the first threshold number of the write responses have not been received within the first response time period, indicate a write failure.

12. The DS module of claim 10 further comprises:

the second module, when operable within the computing device, further causes the computing device to;

when the at least the first threshold number of the write responses have been received within the first response time period and the at least the first threshold number is equal to the total number, issue a set of write commit commands corresponding to the set of encoded data slices.

13. The DS module of claim 10 further comprises:

the third module, when operable within the computing device, further causes the computing device to;

when the at least the second threshold number of the write responses have not been received within the second response time period, issue a second sub-set of write commit commands corresponding to a second response number of encoded data slices for which the write response was received prior to expiration of the second response time period.

14. The DS module of claim 10 further comprises:

the third module, when operable within the computing device, further causes the computing device to;

when the at least the second threshold number of the write responses have been received within the second response time period and the at least the second threshold number is equal to the total number, issue a set of write commit commands corresponding to the set of encoded data slices.

15. The DS module of claim 10 further comprises:

the fourth module, when operable within the computing device, further causes the computing device to;

when the total number of write responses have been received within the third response time period, issue a set of write commit commands corresponding to the set of encoded data slices.

16. The DS module of claim 10 further comprises:

the fourth module, when operable within the computing device, further causes the computing device to;

prior to expiration of the third response time period, determine whether at least a fourth threshold number of write responses have been received within a fourth response time period, wherein the fourth threshold number is less than the total number and wherein the fourth response time period is a portion of the third response time period and is subsequent to the second response time period; and

when the at least the fourth threshold number of the write responses have been received within the fourth response time period and the at least the fourth threshold number is less than the total number, determine whether the total number of write responses have been received within the third response time period.

17. The DS module of claim 10 further comprises:

a sixth module, when operable within the computing device, causes the computing device to;

pre-establish the first, second, and third response time periods.

18. The DS module of claim 10 further comprises:

a sixth module, when operable within the computing device, causes the computing device to;

determine the second response time period based on the first response time period and the receiving of the at least the first threshold number of write responses; and

determine the third response time period based on the receiving of the at least the second threshold number of write responses.