HANDLING UNAVAILABLE MEMORIES IN DISTRIBUTED STORAGE NETWORK

• US 20110078277A1
• Filed: 05/11/2010
• Published: 03/31/2011
• Est. Priority Date: 09/29/2009
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: BAPTIST, ANDREW
• Granted Patent: US 8,918,534 B2
• Time in Patent Office: Days
• US Class Current: 709/217
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 2211/1011 Clustered RAID, i.e. clustered or de-clustered RAID where data and parity are spread over more disks than blocks in a parity group
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• 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: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions
• 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: H04N 21/231 Content storage operation, e.g. caching movies for short term storage, replicating data over plural servers, prioritizing data for deletion
• CPC Class Codes: H04N 21/2405 Monitoring of the internal components or processes of the server, e.g. server load allocation of resources in multiprogramming arrangements G06F9/50; performance measurement of computer activity G06F11/34
• CPC Class Codes: H04N 21/442 Monitoring of processes or resources, e.g. detecting the failure of a recording device, monitoring the downstream bandwidth, the number of times a movie has been viewed, the storage space available from the internal hard disk arrangements for monitoring broadcast services or broadcast-related services H04H60/29; arrangements for identifying or recognising characteristics with a direct linkage to broadcast information H04H60/35; monitoring of user activities for profile generation for accessing a video database G06F16/739; monitoring in wireless networks H04W24/00

Abstract

A distributed storage network includes a distributed storage processing unit, which generates multiple data slices from a single data segment, and multiple different storage units to store the data slices. Each data slice is assigned to a particular storage unit for storage. The distributed storage processing unit determines which of the storage units are in a ready state, and sends data slices to the ready storage units. Data slices assigned to storage units that are not in a ready state are temporarily stored in a temporary memory, e.g. cache memory, until the storage unit becomes ready. If the intended storage unit remains in a non-ready status for too long, the slices stored in cache memory can be sent to a substitute storage unit, or discarded and reconstructed at a later time.

Claims

1. A method of operating a distributed storage processing unit, the method comprising:

creating a plurality of data slices from a data segment, the plurality of data slices to be stored in a distributed storage network including a plurality of storage units;

identifying selected storage units of the plurality of storage units, each of the selected storage units to store particular data slices of the plurality of data slices;

determining which of the selected storage units is in a ready status, wherein a ready status indicates a readiness to receive data slices for storage;

sending data slices to selected storage units in the ready status; and

temporarily storing in a temporary memory data slices intended for selected storage units in a non-ready status.

2. The method of claim 1, further comprising:

sending data slices to the selected storage units only if a number of selected storage units in the ready status is at least as great as a threshold number of data slices.

3. The method of claim 2, further comprising:

discarding data slices associated with a particular selected storage unit from the temporary memory in accordance with a discard policy.

4. The method of claim 1, further comprising:

determining that a particular selected storage unit previously in a non-ready status has entered a ready status; and

in response to the determining, moving the data slices intended for the particular selected storage unit from the temporary memory into the particular selected storage unit.

5. The method of claim 1, further comprising:

determining that a particular selected storage unit has remained in a non-ready status longer than a timeout threshold;

in response to the determining;

selecting a replacement storage unit; and

moving the data slices intended for the particular selected storage unit from the temporary memory into the replacement storage unit.

6. The method of claim 1, further comprising:

temporarily storing the data slices intended for selected storage units in a non-ready status in a temporary memory of the distributed storage processing unit.

7. The method of claim 1, further comprising:

temporarily storing the data slices intended for a particular selected storage unit in a non-ready status in a temporary memory of the particular selected storage processing unit.

8. A distributed storage processing unit comprising:

a processor to;

create a plurality of data slices from a data segment, the plurality of data slices to be stored in a distributed storage network including a plurality of storage units;

identify selected storage units of the plurality of storage units, each of the selected storage units to store particular data slices of the plurality of data slices;

determine which selected storage units is in a ready status, wherein a ready status indicates a readiness to receive data slices for storage;

send data slices to selected storage units in the ready status; and

the processor further to direct delivery of data slices intended for selected storage units in a non-ready status to a temporary memory.

9. The distributed storage processing unit of claim 8, the processor further to:

send data slices to the selected storage units only if a number of selected storage units in the ready status is at least as great as a threshold number of data slices.

10. The distributed storage processing unit of claim 9, the processor further to:

discard data slices associated with a particular selected storage unit from the temporary memory in accordance with a discard policy.

11. The distributed storage processing unit of claim 8, the processor further to:

determine that a particular selected storage unit previously in a non-ready status has entered a ready status; and

direct the movement of data slices intended for the particular selected storage unit from the temporary memory into the particular selected storage unit.

12. The distributed storage processing unit of claim 8, the processor further to:

determine that a particular selected storage unit has remained in a non-ready status longer than a timeout threshold;

select a replacement storage unit; and

direct the movement of data slices intended for the particular selected storage unit from the temporary memory into the replacement storage unit.

13. The distributed storage processing unit of claim 8, the processor further to:

direct data slices intended for selected storage units in a non-ready status to be stored in a temporary memory of the distributed storage processing unit.

14. The distributed storage processing unit of claim 8, the processor further to:

direct data slices intended for a particular selected storage unit in a non-ready status to be stored in a temporary memory of the particular selected storage unit.

15. A distributed storage network comprising:

a plurality of distributed storage units to receive data slices for storage;

a distributed storage processing unit to;

create a plurality of data slices from a data segment, the plurality of data slices to be stored in selected distributed storage units;

identify the selected distributed storage units, each of the selected storage units to store particular data slices of the plurality of data slices;

determine which of the selected distributed storage units is in a ready status, wherein a ready status indicates a readiness to receive data slices for storage;

send data slices to selected distributed storage units having a status of ready; and

direct delivery of data slices intended for selected distributed storage units having a status of non-ready to a temporary memory.

16. The distributed storage network of claim 15, further comprising:

the distributed storage processing unit to send data slices to the selected distributed storage units only if a number of selected distributed storage units having a status of ready is at least as great as a threshold number of data slices.

17. The distributed storage network of claim 16, further comprising:

the distributed storage processing unit to discard data slices associated with a particular selected storage unit from the temporary memory in accordance with a discard policy.

18. The distributed storage network of claim 15, further comprising:

the distributed storage processing unit to determine that a particular selected distributed storage unit previously in a non-ready status has entered a ready status; and

the distributed storage processing unit further to direct the movement of data slices intended for the particular selected distributed storage unit from the temporary memory into the particular selected distributed storage unit.

19. The distributed storage network of claim 15, further comprising:

the distributed storage processing unit to;

determine that a particular selected distributed storage unit has remained in a non-ready status longer than a timeout threshold;

select a replacement distributed storage unit; and

direct the movement of data slices intended for the particular selected distributed storage unit from the temporary memory into the replacement distributed storage unit.

20. The distributed storage network of claim 15, further comprising:

a local temporary memory local to and associated with the distributed storage processing unit; and

the distributed storage processing unit to direct data slices intended for selected distributed storage units in a non-ready status to be stored in the local temporary memory associated with the distributed storage processing unit.

21. The distributed storage network of claim 15, further comprising:

a local temporary memory local to and associated with a particular distributed storage unit in a non-ready status; and

the distributed storage processing unit to direct data slices intended to be stored in the particular selected distributed storage unit, be stored temporarily in the local temporary memory of the particular selected distributed storage unit.