Storing data in accordance with a performance threshold

• US 9,405,609 B2
• Filed: 04/18/2014
• Issued: 08/02/2016
• Est. Priority Date: 05/22/2013
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Dhuse, Greg, Resch, Jason K., Shirley, Thomas Franklin Jr.
• Primary Examiner(s): Chu, Gabriel
• Application Number:
  US14/256,536
• Publication Number:
  US 20140351659A1
• Time in Patent Office: 837 Days
• Field of Search: None
• US Class Current: 1/1
• 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 16/2379 Updates performed during online database operations; commit processing
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• 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 3/067 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

In response to a write operation for a set of encoded data slices, a method begins by a dispersed storage (DS) processing module determining whether to use a performance threshold number of encoded data slices of the set of encoded data slices. When the performance threshold number of encoded data slices is to be used, the method continues with the DS processing module determining the performance threshold number of encoded data slices and sending a performance threshold number of initial phase write requests to storage units. When a write threshold number of write responses are received, the method continues with the DS processing module sending a number of next phase write requests to the storage units, where the number of next phase write requests is equal to or greater than the write threshold number and is less than or equal to the performance threshold number.

Claims

1. A method for execution by one or more processing modules of a computing device of a dispersed storage network (DSN), the method comprises:

in response to a write operation for a set of encoded data slices, determining whether to use a performance threshold number of encoded data slices of the set of encoded data slices, wherein a segment of data is dispersed storage error encoded into the set of encoded data slices having a total number of encoded data slices, wherein a decode threshold number of encoded data slices is required to reconstruct the segment of data, and wherein the performance threshold number is less than the total number; and

when the performance threshold number of encoded data slices is to be used;

determining the performance threshold number of encoded data slices;

sending a performance threshold number of initial phase write requests regarding the performance threshold number of encoded data slices to storage units of the DSN; and

when a write threshold number of write responses are received from at least some of the storage units in response to the performance threshold number of initial phase write requests, sending a number of next phase write requests to the storage units, wherein the number of next phase write requests is equal to or greater than the write threshold number and is less than or equal to the performance threshold number, wherein the write threshold number is equal to or greater than the decode threshold number and is less than or equal to the performance threshold number.

2. The method of claim 1 further comprises:

for each remaining encoded data slice of a remaining number of encoded data slices of the set of encoded data slices, determining whether to flag the remaining encoded data slice for a delayed write operation to the DSN or determining whether to flag the remaining encoded data slice for rebuilding, wherein the remaining number is equal to a difference between the total number and the performance threshold number;

when the remaining encoded data slice is flagged for the rebuilding, storing a slice name of the remaining encoded data slice in a rebuild queue; and

when the remaining encoded data slice is flagged for the delayed write operation, storing the remaining encoded data slice in a delayed write operation queue.

3. The method of claim 1, wherein the sending the number of next phase write requests comprises:

determining whether to adjust the performance threshold number for a corresponding next phase of the write operation;

when the performance threshold number for the corresponding next phase of the write operation is to be adjusted, adjusting the performance threshold number to an adjusted performance threshold number that is less than the performance threshold number and is equal to or greater than the write threshold number; and

setting the number of the next phase write requests to the adjusted performance threshold number.

4. The method of claim 1 further comprises:

when a write threshold number of next phase write responses are received from at least some of the storage units in response to the number of next phase write requests, sending a second number of second next phase write requests to the storage units, wherein the second number of the second next phase write requests is equal to or greater than the write threshold number and is less than or equal to the performance threshold number.

5. The method of claim 4, wherein the sending the second number of the second next phase write requests comprises:

determining whether, to adjust the number for a corresponding second next phase of the write operation, to set the second number equal to the number of the next phase write requests or to adjust the second number from the number of the next phase write requests;

when the second number for the corresponding second next phase of the write operation is to be adjusted from the number of the next phase write requests, adjusting the number of the next phase write requests to an adjusted number that is less than the number and is equal to or greater than the write threshold number; and

setting the second number of the second next phase write requests to the adjusted number.

6. The method of claim 1, wherein the determining the performance threshold number of encoded data slices comprises:

obtaining storage performance information for the storage units;

interpreting the storage performance information to identify one or more of the storage units having a less than desired storage performance level; and

determining the performance threshold number based on the total number and on the one or more of the storage units having the less than desired storage performance level.

7. The method of claim 1, wherein a storage performance information comprises one or more of:

storage capacity;

storage availability;

access response latency;

hardware failure data; and

storage access bandwidth.

8. The method of claim 1 further comprises:

discarding, for the write operation, a remaining number of encoded data slices of the set of encoded data slices, wherein the remaining number is equal to a difference between the total number and the performance threshold number.

9. The method of claim 1, wherein the determining whether to use the performance threshold number of encoded data slices comprises at least one of:

determining whether to use the performance threshold number of encoded data slices based on memory performance characteristics of memory of the computing device being less than a desired memory performance level;

determining whether to use the performance threshold number of encoded data slices based on setting of a performance threshold flag; and

determining whether to use the performance threshold number of encoded data slices based on a DSN setting.

10. The method of claim 1 further comprises:

when the performance threshold number of encoded data slices is not to be used;

sending a total number of initial phase write requests regarding the set of encoded data slices to the storage units; and

when a write threshold number of write responses are received from at least some of the storage units in response to the total number of initial phase write requests, sending the number of next phase write requests to the storage units, wherein the number of next phase write requests is equal to or greater than the write threshold number and is less than or equal to the total number, wherein the write threshold number is equal to or greater than the decode threshold number and is less than or equal to the total number.

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

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

in response to a write operation for a set of encoded data slices, determine whether to use a performance threshold number of encoded data slices of the set of encoded data slices, wherein a segment of data is dispersed storage error encoded into the set of encoded data slices having a total number of encoded data slices, wherein a decode threshold number of encoded data slices is required to reconstruct the segment of data, and wherein the performance threshold number is less than the total number; and

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

when the performance threshold number of encoded data slices is to be used;

determine the performance threshold number of encoded data slices;

send a performance threshold number of initial phase write requests regarding the performance threshold number of encoded data slices to storage units of the DSN; and

when a write threshold number of write responses are received from at least some of the storage units in response to the performance threshold number of initial phase write requests, send a number of next phase write requests to the storage units, wherein the number of next phase write requests is equal to or greater than the write threshold number and is less than or equal to the performance threshold number, wherein the write threshold number is equal to or greater than the decode threshold number and is less than or equal to the performance threshold number.

12. The DS module of claim 11 further comprises:

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

for each remaining encoded data slice of a remaining number of encoded data slices of the set of encoded data slices, determine whether to flag the remaining encoded data slice for a delayed write operation to the DSN or determine whether to flag the remaining encoded data slice for rebuilding, wherein the remaining number is equal to a difference between the total number and the performance threshold number;

when the remaining encoded data slice is flagged for the rebuilding, store a slice name of the remaining encoded data slice in a rebuild queue; and

when the remaining encoded data slice is flagged for the delayed write operation, store the remaining encoded data slice in a delayed write operation queue.

13. The DS module of claim 11, wherein the second module causes the computing device to

send the number of next phase write requests by:

determining whether to adjust the performance threshold number for a corresponding next phase of the write operation;

when the performance threshold number for the corresponding next phase of the write operation is to be adjusted, adjusting the performance threshold number to an adjusted performance threshold number that is less than the performance threshold number and is equal to or greater than the write threshold number; and

setting the number of the next phase write requests to the adjusted performance threshold number.

14. The DS module of claim 11 further comprises:

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

when a write threshold number of next phase write responses are received from at least some of the storage units in response to the number of next phase write requests, send a second number of a second next phase write requests to the storage units, wherein the second number of the second next phase write requests is equal to or greater than the write threshold number and is less than or equal to the performance threshold number.

15. The DS module of claim 14, wherein the second module causes the computing device to:

send the second number of the second next phase write requests by;

determining whether to adjust the number for a corresponding second next phase of the write operation;

determining whether, to adjust the number for a corresponding second next phase of the write operation, to set the second number equal to the number of the next phase write requests or to adjust the second number from the number of the next phase write requests;

when the second number for the corresponding second next phase of the write operation is to be adjusted from the number of the next phase write requests, adjusting the number of the next phase write requests to an adjusted number that is less than the number and is equal to or greater than the write threshold number; and

setting the second number of the second next phase write requests to the adjusted number.

16. The DS module of claim 11, wherein the second module causes the computing device to determine the performance threshold number of encoded data slices by:

obtaining storage performance information for the storage units;

interpreting the storage performance information to identify one or more of the storage units having a less than desired storage performance level; and

determining the performance threshold number based on the total number and on the one or more of the storage units having the less than desired storage performance level.

17. The DS module of claim 11, wherein a storage performance information comprises one or more of:

storage capacity;

storage availability;

access response latency;

hardware failure data; and

storage access bandwidth.

18. The DS module of claim 11 further comprises:

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

discard, for the write operation, a remaining number of encoded data slices of the set of encoded data slices, wherein the remaining number is equal to a difference between the total number and the performance threshold number.

19. The DS module of claim 11, wherein the first module causes the computing device to determine whether to use the performance threshold number of encoded data slices by at least one of:

determining whether to use the performance threshold number of encoded data slices based on memory performance characteristics of memory of the computing device being less than a desired memory performance level;

determining whether to use the performance threshold number of encoded data slices based on setting of a performance threshold flag; and

determining whether to use the performance threshold number of encoded data slices based on a DSN setting.

20. The DS module of claim 11 further comprises:

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

when the performance threshold number of encoded data slices is not to be used;

send a total number of initial phase write requests regarding the set of encoded data slices to the storage units; and

when a write threshold number of write responses are received from at least some of the storage units in response to the total number of initial phase write requests, send the number of next phase write requests to the storage units, wherein the number of next phase write requests is equal to or greater than the write threshold number and is less than or equal to the total number, wherein the write threshold number is equal to or greater than the decode threshold and is less than or equal to the total number.