DISTRIBUTED STORAGE NETWORK MEMORY ACCESS BASED ON MEMORY STATE

• US 20130283125A1
• Filed: 06/24/2013
• Published: 10/24/2013
• Est. Priority Date: 09/29/2009
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Gladwin, S. Christopher, Leggette, Wesley
• Granted Patent: US 9,274,890 B2
• Time in Patent Office: Days
• US Class Current: 714/758
• 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 storage device of a DSN includes a plurality of memory devices, an interface, and a processing module. The storage device receives an encoded data slice of a set of encoded data slices, wherein a data segment is dispersed storage error encoded to produce the set of encoded data slices. The dispersed storage error encoding includes arranging the data segment into a data matrix of data blocks, generating an encoded data matrix from the data matrix and an encoding matrix, and arranging encoded data blocks of the encoded data matrix into the set of encoded data slices. The storage unit then divides the encoded data slice into encoded data slice partitions and generates a parity data partition therefrom. The storage device then stores the encoded data slice partitions and the parity data partition in separate memory devices.

Claims

1. A method for execution by one or more devices of a distributed storage network (DSN), the method comprises:

dispersed storage error encoding a data segment to produce a set of encoded data slices, wherein the dispersed storage error encoding includes arranging the data segment into a data matrix of data blocks, generating an encoded data matrix from the data matrix and an encoding matrix, and arranging encoded data blocks of the encoded data matrix into the set of encoded data slices;

receiving, by a storage device of the DSN, an encoded data slice of the set of encoded data slices;

dividing, by the storage device, the encoded data slice into encoded data slice partitions;

generating, by the storage device, a parity data partition based on the encoded data slice partitions;

storing, by the storage device, the encoded data slice partitions in separate memory devices of a plurality of memory devices of the storage unit; and

storing, by the storage device, the parity data partition in another separate memory of the plurality of memory devices.

2. The method of claim 1 further comprises:

maintaining, by the storage device, memory states of the plurality of memory devices, wherein the memory states include a write only state, a read state, and a write with read priority state;

establishing, by the storage device, the write only state for the separate memory devices and the other separate memory device prior to storing the encoded data slice partitions and the parity data partition.

3. The method of claim 1 further comprises:

receiving, by a second storage device of the DSN, a second encoded data slice of the set of encoded data slices;

dividing, by the second storage device, the second encoded data slice into second encoded data slice partitions;

generating, by the second storage device, a second parity data partition based on the second encoded data slice partitions;

storing, by the second storage device, the second encoded data slice partitions in separate memory devices of a plurality of memory devices of the second storage unit; and

storing, by the second storage device, the parity data partition in another separate memory of the plurality of memory devices of the second storage unit.

4. The method of claim 3 further comprises:

maintaining, by the second storage device, memory states of the plurality of memory devices, wherein the memory states include a write only state, a read state, or a write with read priority state;

establishing, by the second storage device, the write only state for the separate memory devices and the other separate memory device prior to storing the second encoded data slice partitions and the second parity data partition.

5. The method of claim 1 further comprises:

receiving, by the storage unit, a read request for the encoded data slice;

determining, by the storage unit, memory state of the separate memory devices and the other separate memory devices, wherein the memory state is one of a write state, a read state, or a write with read priority state;

when the separate memory devices are in the read state or when the other separate memory device and a sufficient number of the separate memory devices are in the read state, reconstructing, by the storage unit, the encoded data slice from the encoded data slice partitions or from a sufficient number of the encoded slice partitions and the data parity partition; and

outputting, by the storage device, the reconstructed encoded data slice.

6. The method of claim 5 further comprises:

when the separate memory devices are in the write with read priority state or when the other separate memory device and a sufficient number of the separate memory devices are in the write with read priority state, pausing, by the storage unit, write requests to the separate memory devices and to the other separate memory device;

when the write requests to the separate memory devices and to the other separate memory device are paused, reconstructing, by the storage unit, the encoded data slice from the encoded data slice partitions or from a sufficient number of the encoded slice partitions and the data parity partition; and

outputting, by the storage device, the reconstructed encoded data slice.

7. The method of claim 5 further comprises:

when the separate memory devices are in the write state or when the other separate memory device and a sufficient number of the separate memory devices are in the write state, sending, by the storage unit, a read response message indicating a denial of the read request.

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

a plurality of memory devices;

an interface; and

a processing module operable to;

receive, via the interface, an encoded data slice of a set of encoded data slices, wherein a data segment is dispersed storage error encoded to produce the set of encoded data slices, wherein the dispersed storage error encoding includes arranging the data segment into a data matrix of data blocks, generating an encoded data matrix from the data matrix and an encoding matrix, and arranging encoded data blocks of the encoded data matrix into the set of encoded data slices;

divide the encoded data slice into encoded data slice partitions;

generate a parity data partition based on the encoded data slice partitions;

store the encoded data slice partitions in separate memory devices of the plurality of memory devices of the storage unit; and

store the parity data partition in another separate memory of the plurality of memory devices.

9. The storage device of claim 8, wherein the processing module is further operable to:

maintain memory states of the plurality of memory devices, wherein the memory states include a write only state, a read state, and a write with read priority state;

establish the write only state for the separate memory devices and the other separate memory device prior to storing the encoded data slice partitions and the parity data partition.

10. The storage device of claim 8, wherein the processing module is further operable to:

receive, via the interface, a read request for the encoded data slice;

determine memory state of the separate memory devices and the other separate memory devices, wherein the memory state is one of a write state, a read state, or a write with read priority state;

when the separate memory devices are in the read state or when the other separate memory device and a sufficient number of the separate memory devices are in the read state, reconstruct the encoded data slice from the encoded data slice partitions or from a sufficient number of the encoded slice partitions and the data parity partition; and

output, via the interface, the reconstructed encoded data slice.

11. The storage device of claim 10, wherein the processing module is further operable to:

when the separate memory devices are in the write with read priority state or when the other separate memory device and a sufficient number of the separate memory devices are in the write with read priority state, pause write requests to the separate memory devices and to the other separate memory device;

when the write requests to the separate memory devices and to the other separate memory device are paused, reconstruct the encoded data slice from the encoded data slice partitions or from a sufficient number of the encoded slice partitions and the data parity partition; and

output, via the interface, the reconstructed encoded data slice.

12. The storage device of claim 10, wherein the processing module is further operable to:

when the separate memory devices are in the write state or when the other separate memory device and a sufficient number of the separate memory devices are in the write state, send, via the interface, a read response message indicating a denial of the read request.