Priority level adaptation in a dispersed storage network

• US 10,318,445 B2
• Filed: 09/02/2016
• Issued: 06/11/2019
• Est. Priority Date: 11/28/2011
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Dhuse, Greg R.
• Primary Examiner(s): Joshi, Suraj M
• Assistant Examiner(s): Habtemariam, Melaku Y
• Application Number:
  US15/255,540
• Publication Number:
  US 20160371202A1
• Time in Patent Office: 1,012 Days
• Field of Search: 709203-207, 709217
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 12/0607 Interleaved addressing
• CPC Class Codes: G06F 13/1626 by reordering requests
• CPC Class Codes: G06F 13/1663 Access to shared memory
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 21/78 to assure secure storage of data address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 3/0608 Saving storage space on storage systems
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0641 De-duplication techniques
• CPC Class Codes: G06F 3/065 Replication mechanisms
• 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 63/101 Access control lists [ACL]
• 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 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions

Abstract

A processing system in a dispersed storage network is configured to access write sequence information corresponding to a write sequence; determine whether to elevate a priority level of the write sequence; when the processing system determines to elevate the priority level of the write sequence, elevate the priority level of the write sequence; determine whether to lower the priority level of the write sequence; and when the processing system determines to lower the priority level of the write sequence, the processing system lowers the priority level of the write sequence.

Claims

1. A method for execution by a dispersed storage and task (DST) processing unit that includes a processor, the method comprises:

accessing, via the processor, write sequence information corresponding to a write sequence;

determining, via the processor, whether to elevate a priority level of the write sequence based on determining when the write sequence is associated with an oldest write sequence of a plurality of other write sequences that has not received a write threshold number of favorable write responses;

when the processor determines to elevate the priority level of the write sequence, the processor elevates the priority level of the write sequence;

determining, via the processor, whether to lower the priority level of the write sequence; and

when the processor determines to lower the priority level of the write sequence, the processor lowers the priority level of the write sequence.

2. The method of claim 1 wherein the write sequence information includes one or more of:

a queue depth, a priority level of a pending request, an age of a pending request, a number of favorable write responses received, and the write threshold number.

3. The method of claim 1 wherein the accessing is based on one or more of:

retrieving a message queue, a lookup, receiving a request, a query, and an error message.

4. The method of claim 1 wherein the priority level of the write sequence is utilized in determining a transmission order of two or more pending write request messages of a common queue, wherein a write request associated with a higher priority level is transmitted prior to a write request associated with a lower priority level.

5. The method of claim 1 wherein determining to elevate the priority level of the write sequence is based on the write sequence information.

6. The method of claim 1 wherein at least one of the plurality of other write sequences is associated with a different write threshold number.

7. The method of claim 1 wherein determining to elevate the priority level of the write sequence is further based on determining when the write sequence is associated with a highest priority write sequence of the plurality of other write sequences that has not received the write threshold number of favorable write responses.

8. The method of claim 1 wherein elevating of the priority level includes at least one of:

modifying a priority level indicator of an associated write request in a queue to include a higher priority level number, and reordering pending write requests in the queue such that highest priority requests will be transmitted after the associated write request.

9. The method of claim 1 wherein determining to lower the priority level of the write sequence is based on the write sequence information.

10. The method of claim 1 wherein determining to elevate the priority level of the write sequence is further based on determining when the write sequence is associated with another write sequence of the plurality of other write sequences that has received the write threshold number of favorable write responses.

11. The method of claim 1 wherein determining to elevate the priority level of the write sequence is further based on determining when the write sequence is associated with a highest priority write sequence of the plurality of other write sequences that has received the write threshold number of favorable write responses.

12. The method of claim 1 wherein lowering of the priority level includes at least one of:

modifying a priority level indicator of an associated write request in a queue to include a lower priority level number, or reordering pending write requests in the queue such that highest priority requests will be transmitted before the associated write request.

13. A processing system of a dispersed storage network comprises:

at least one processor;

a memory that stores operational instructions, that when executed by the at least one processor cause the processing system to;

access write sequence information corresponding to a write sequence;

determine whether to elevate a priority level of the write sequence based on determining when the write sequence is associated with an oldest write sequence of a plurality of other write sequences that has not received a write threshold number of favorable write responses;

when the processing system determines to elevate the priority level of the write sequence, elevate the priority level of the write sequence;

determine whether to lower the priority level of the write sequence; and

when the processing system determines to lower the priority level of the write sequence, lower the priority level of the write sequence.

14. The processing system of claim 13 wherein the write sequence information includes one or more of:

a queue depth, a priority level of a pending request, an age of a pending request, a number of favorable write responses received, and the write threshold number.

15. The processing system of claim 13 wherein the priority level of the write sequence is utilized in determining a transmission order of two or more pending write request messages of a common queue, wherein a write request associated with a higher priority level is transmitted prior to a write request associated with a lower priority level.

16. The processing system of claim 13 wherein determining to elevate the priority level of the write sequence is further based on determining when the write sequence is associated with a highest priority write sequence of the plurality of other write sequences that has not received the write threshold number of favorable write responses.

17. The processing system of claim 13 wherein determining to elevate the priority level of the write sequence is further based on determining when the write sequence is associated with a highest priority write sequence of the plurality of other write sequences that has received the write threshold number of favorable write responses.

18. The processing system of claim 13 wherein the accessing is based on one or more of:

retrieving a message queue, a lookup, receiving a request, a query, and an error message.

19. A non-transitory computer readable storage medium comprises:

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

access write sequence information corresponding to a write sequence;

determine whether to elevate a priority level of the write sequence based on determining when the write sequence is associated with an oldest write sequence of a plurality of other write sequences that has not received a write threshold number of favorable write responses;

when the processing system determines to elevate the priority level of the write sequence, elevate the priority level of the write sequence;

determine whether to lower the priority level of the write sequence; and

when the processing system determines to lower the priority level of the write sequence, lower the priority level of the write sequence.