Revision synchronization of a dispersed storage network

• US 9,152,489 B2
• Filed: 10/13/2010
• Issued: 10/06/2015
• Est. Priority Date: 12/29/2009
• Status: Expired due to Fees

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Baptist, Andrew, Leggette, Wesley, Volvovski, Ilya, Resch, Jason K., Dhuse, Greg, Cilfone, Bart
• Primary Examiner(s): Li, Aimee
• Assistant Examiner(s): Thammavong, Prasith
• Application Number:
  US12/903,209
• Publication Number:
  US 20110161754A1
• Time in Patent Office: 1,819 Days
• Field of Search: 711/147, 711/141
• US Class Current: 1/1
• CPC Class Codes: G06F 11/0745 in an input/output transactions management context input/output processing in general G06F13/00
• CPC Class Codes: G06F 11/1064 in cache or content addressable memories
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 11/1443 Transmit or communication errors
• CPC Class Codes: G06F 11/1471 involving logging of persistent data for recovery
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 12/0815 Cache consistency protocols
• CPC Class Codes: G06F 21/10 Protecting distributed programs or content, e.g. vending or licensing of copyrighted material protection in video systems or pay television H04N7/16 ; Digital rights management [DRM]
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 2211/1057 Parity-multiple bits-RAID6, i.e. RAID 6 implementations
• CPC Class Codes: G06F 9/467 Transactional memory G06F9/528 takes precedence

Abstract

A method begins by a processing module receiving a write request message from a dispersed storage (DS) processing module, wherein the write request message includes a slice name, a DS processing module most-recent slice revision, a new slice revision, and an encoded directory slice of directory information regarding storage of data. The method continues with the processing module obtaining, from local memory, a DS unit most-recent slice revision based on the slice name. The method continues with the processing module storing the new slice revision as the DS unit most-recent slice revision and storing the encoded directory slice when the DS unit most-recent slice revision compares favorably to the DS processing module most-recent slice revision.

Claims

1. A method for execution by a dispersed storage (DS) unit, the method comprises:

receiving a write request message from a dispersed storage (DS) processing module, wherein the write request message includes a slice name, a DS processing module most-recent slice revision, a new slice revision, and an encoded directory slice of directory information regarding storage of data;

obtaining, from local memory, a DS unit most-recent slice revision based on the slice name; and

when a revision number of the DS unit most-recent slice revision is same as a revision number of the DS processing module most-recent slice revision;

storing the new slice revision as the DS unit most-recent slice revision; and

storing the encoded directory slice.

2. The method of claim 1 further comprises:

generating a write response message that includes an operation succeeded status code; and

sending the write response message to the DS processing module.

3. The method of claim 1 further comprises:

when the revision number of the DS unit most-recent slice revision is not the same as the revision number of the DS processing module most-recent slice revision;

generating a write response message to include a condition status code indicating an unfavorable comparison of the revision numbers; and

sending the write response message to the DS processing module.

4. The method of claim 1 further comprises:

receiving the write request message, wherein the write request message further includes a DS processing module transaction identifier;

determining whether the slice name has a locked state based on a local state indicator; and

when the slice name has the locked state and a DS unit transaction identifier associated with the encoded directory slice is different than the DS processing module transaction identifier;

generating a write response message that includes a transaction conflict status code; and

sending the write response message to the DS processing module.

5. The method of claim 4 further comprises:

when the slice name does not have a locked state;

updating the local state indicator to indicate that the slice name has the locked state; and

storing the DS processing module transaction identifier as the DS unit transaction identifier.

6. A dispersed storage (DS) unit comprises:

an interface;

a local memory; and

a processing module operable to;

receive, via the interface, a write request message from a dispersed storage (DS) processing module, wherein the write request message includes a slice name, a DS processing module most-recent slice revision, a new slice revision, and an encoded directory slice of directory information regarding storage of data;

obtain, from the local memory, a DS unit most-recent slice revision based on the slice name; and

when a revision number of the DS unit most-recent slice revision is same as a revision number of the DS processing module most-recent slice revision;

store, in the local memory, the new slice revision as the DS unit most-recent slice revision; and

store, in the local memory, the encoded directory slice.

7. The DS unit of claim 6, wherein the processing module further functions to:

generate a write response message that includes an operation succeeded status code; and

send, via the interface, the write response message to the DS processing module.

8. The DS unit of claim 6, wherein the processing module further functions to:

when the revision number of the DS unit most-recent slice revision is not the same as the revision number of the DS processing module most-recent slice revision;

generate a write response message to include a condition status code indicating an unfavorable comparison of the revision numbers; and

send, via the interface, the write response message to the DS processing module.

9. The DS unit of claim 6, wherein the processing module further functions to:

receive, via the interface, the write request message, wherein the write request message further includes a DS processing module transaction identifier;

determine whether the slice name has a locked state based on a local state indicator; and

when the slice name has the locked state and a DS unit transaction identifier associated with the encoded directory slice is different than the DS processing module transaction identifier;

generate a write response message that includes a transaction conflict status code; and

send, via the interface, the write response message to the DS processing module.

10. The DS unit of claim 9, wherein the processing module further functions to:

when the slice name does not have a locked state;

update, in the local memory, the local state indicator to indicate that the slice name has the locked state; and

store, in the local memory, the DS processing module transaction identifier as the DS unit transaction identifier.