Identifying and correcting an undesired condition of a dispersed storage network access request

• US 8,782,227 B2
• Filed: 06/07/2011
• Issued: 07/15/2014
• Est. Priority Date: 06/22/2010
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Resch, Jason K., Dhuse, Greg, Baptist, Andrew
• Primary Examiner(s): KHAJURIA, SHRIPAL K
• Application Number:
  US13/154,708
• Publication Number:
  US 20110314154A1
• Time in Patent Office: 1,134 Days
• Field of Search: 709/225
• US Class Current: 709/225
• CPC Class Codes: G06F 11/0727 in a storage system, e.g. in a DASD or network based storage system drivers for digital recording or reproducing units G06F3/06; circuits for error detection or correction within digital recording or reproducing units G11B20/18; 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], H04L67/1097
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 11/141 for bus or memory accesses
• CPC Class Codes: G06F 11/167 Error detection by comparing the memory output
• CPC Class Codes: G06F 16/13 File access structures, e.g. distributed indices arrangements of input from, or output to, record carriers G06F3/06
• CPC Class Codes: G06F 16/137 Hash-based content-based indexing of textual data G06F16/31
• CPC Class Codes: G06F 21/31 User authentication
• 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 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: H04L 2209/043 of tables, e.g. lookup, substitution or mapping
• CPC Class Codes: H04L 2209/30 Compression, e.g. Merkle-Damgard construction
• CPC Class Codes: H04L 2209/34 Encoding or coding, e.g. Huffman coding or error correction
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/80 Wireless
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/06 for supporting key management in a packet data network cryptographic mechanisms or cryptographic arrangements for key management H04L9/08
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• 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 9/3242 involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC
• CPC Class Codes: H04L 9/3247 : involving digital signatures
• CPC Class Codes: H04L 9/3263 : involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823
• CPC Class Codes: H04L 9/3271 : using challenge-response
• CPC Class Codes: H04W 12/041 : Key generation or derivation
• CPC Class Codes: H04W 12/0431 : Key distribution or pre-distribution; Key agreement
• CPC Class Codes: H04W 12/10 : Integrity
• CPC Class Codes: H04W 12/35 : Protecting application or service provisioning, e.g. securing SIM application provisioning

Abstract

A method begins by a processing module sending a transaction verification request to the set of dispersed storage (DS) units, wherein the transaction verification request includes a transaction number that corresponds to a particular dispersed storage network (DSN) access request. The method continues with the processing module receiving transaction verification responses from at least some of the set of DS units to produce received transaction verification responses. The method continues with the processing module identifying an undesired condition with processing the DSN access request and initiating a corrective remedy for the undesired condition when a DS unit of the set of DS units does not provide a desired transaction verification response.

Claims

1. A method for execution by a computer, the method comprises:

sending a set of transaction verification requests to a set of dispersed storage (DS) units, wherein a transaction verification request of the set of transaction verification requests includes a unique transaction number that corresponds to a particular dispersed storage network (DSN) access request regarding a set of encoded data slices, and wherein another unique transaction number corresponds to another particular DSN access request;

determining a set of transaction verification responses for the set of DS units;

identifying one of the set of transaction verification responses as being inconsistent with other transaction verification responses of the set of transaction responses; and

initiating a corrective remedy for at least one encoded data slice of the set of encoded data slices associated with the one of the set of transaction verification responses.

2. The method of claim 1, wherein the identifying one of the set of transaction verification responses as being inconsistent with other transaction verification responses comprises at least one of:

detecting that the one of the transaction verification responses received from a DS unit of the set of DS units does not include the transaction number;

generating the one of the transaction verification responses when the DS unit does not provide a response to one of the set of transaction verification requests within a given time period;

interpreting the one of the transaction verification responses received from the DS unit to determine that the DS unit did not receive the DSN access request for a corresponding one of the set of encoded data slices; and

detecting that the one of the transaction verification responses received from the DS unit includes a transaction number that is different from the unique transaction number.

3. The method of claim 1 further comprises:

sending, as the DSN access request, a set of access requests to the set of DS units concurrent with, or prior to, sending the set of transaction verification requests to the set of DS units.

4. The method of claim 1 further comprises:

when the desired transaction verification responses are favorable, indicating that the DSN access request is verified.

5. The method of claim 1, wherein the initiating the corrective remedy comprises one or more of:

initiating a rebuild function for the at least one encoded data slice;

resending the DSN access request to the set of DS units;

sending the DSN access request to another set of DS units; and

modifying the DSN access request to produce a modified DSN access request and sending the modified DSN access request to the set of DSN units or the another set of DSN units.

6. The method of claim 5, wherein the initiating the rebuild function comprises at least one of:

rebuilding the at least one encoded data slice to produce at least one rebuilt encoded data slice;

sending a rebuilding request to a rebuilding entity, wherein the request includes a slice name of the at least one encoded data slice and wherein the rebuilding entity rebuilds the at least one encoded data slice; and

sending the slice name to another DS unit for rebuilding the at least one encoded data slice.

7. A computer comprises:

an interface;

a memory; and

a processing module operably coupled to the interface and the memory, wherein the processing module is operable to;

send, via the interface, a set of transaction verification requests to a set of dispersed storage (DS) units, wherein a transaction verification request of the set of transaction verification requests includes a unique transaction number that corresponds to a particular dispersed storage network (DSN) access request regarding a set of encoded data slices, and wherein another unique transaction number corresponds to another particular DSN access request;

determine a set of transaction verification responses for the set of DS units;

identify one of the set of transaction verification responses as being inconsistent with other transaction verification responses of the set of transaction responses; and

initiate a corrective remedy for at least one encoded data slice of the set of encoded data slices associated with the one of the set of transaction verification responses.

8. The computer of claim 7, wherein the processing module functions to identify the one of the set of transaction verification responses as being inconsistent with other transaction verification responses by:

detecting that the one of the transaction verification responses received from a DS unit of the set of DS units does not include the transaction number;

generating the one of the transaction verification responses when the DS unit does not provide a response to one of the set of transaction verification requests within a given time period;

interpreting the one of the transaction verification responses received from the DS unit to determine that the DS unit did not receive the DSN access request for a corresponding one of the set of encoded data slices; and

detecting that the one of the transaction verification responses received from the DS unit includes a transaction number that is different from the unique transaction number.

9. The computer of claim 7, wherein the processing module further functions to:

send, via the interface and as the DSN access request, a set of access requests to the set of DS units concurrent with, or prior to, sending the set of transaction verification requests to the set of DS units.

10. The computer of claim 7, wherein the processing module further functions to:

when the desired transaction verification responses are favorable, indicate that the DSN access request is verified.

11. The computer of claim 7, wherein the processing module functions to initiate the corrective remedy by one or more of:

initiating a rebuild function for the at least one encoded data slice;

resending, via the interface, the DSN access request to the set of DS units;

sending, via the interface, the DSN access request to another set of DS units; and

modifying the DSN access request to produce a modified DSN access request and sending, via the interface, the modified DSN access request to the set of DSN units or the another set of DSN units.

12. The computer of claim 11, wherein the processing module functions to initiate the rebuild function by at least one of:

rebuilding the at least one encoded data slice to produce at least one rebuilt encoded data slice;

sending a rebuilding request to a rebuilding entity, wherein the request includes a slice name of the at least one encoded data slice and wherein the rebuilding entity rebuilds the at least one encoded data slice; and

sending the slice name to another DS unit for rebuilding the at least one encoded data slice.