TIME BASED DISPERSED STORAGE ACCESS

• US 20110161679A1
• Filed: 09/20/2010
• Published: 06/30/2011
• Est. Priority Date: 12/29/2009
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: GRUBE, GARY W., MARKISON, TIMOTHY W.
• Granted Patent: US 8,990,585 B2
• Time in Patent Office: Days
• US Class Current: 713/193
• CPC Class Codes: G06F 11/00 Error detection; Error correction; Monitoring error detection, correction or monitoring in information storage based on relative movement between record carrier and transducer G11B20/18; monitoring, i.e. supervising the progress of recording or reproducing G11B27/36; in static stores G11C29/00
• CPC Class Codes: G06F 11/08 Error detection or correction by redundancy in data representation, e.g. by using checking codes
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 21/60 Protecting data
• CPC Class Codes: G06F 21/62 Protecting access to data via a platform, e.g. using keys or access control rules
• CPC Class Codes: G06F 2211/1028 Distributed, i.e. distributed RAID systems with parity
• CPC Class Codes: G06F 2221/2137 Time limited access, e.g. to a computer or data
• CPC Class Codes: G06F 2221/2141 Access rights, e.g. capability lists, access control lists, access tables, access matrices
• CPC Class Codes: H04L 2012/6467 Information loss recovery, e.g. error correction, prediction
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 63/108 when the policy decisions are valid for a limited amount of time
• 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]

Abstract

A method begins with a processing module receiving a data retrieval request and obtaining a real-time indicator corresponding to when the data retrieval request was received. The method continues with the processing module determining a time-based data access policy based on the data retrieval request and the real-time indicator and accessing a plurality of dispersed storage (DS) units in accordance with the time-based data access policy to retrieve encoded data slices. The method continues with the processing module decoding the threshold number of encoded data slices in accordance with an error coding dispersal storage function when a threshold number of the encoded data slices have been retrieved.

Claims

1. A method comprises:

receiving a data retrieval request;

obtaining a real-time indicator corresponding to when the data retrieval request was received;

determining a time-based data access policy based on the data retrieval request and the real-time indicator;

accessing a plurality of dispersed storage (DS) units in accordance with the time-based data access policy to retrieve encoded data slices; and

when a threshold number of the encoded data slices have been retrieved, decoding the threshold number of encoded data slices in accordance with an error coding dispersal storage function.

2. The method of claim 1, wherein the accessing the plurality of dispersed storage (DS) units comprises:

identifying a first set of DS units of the plurality of DS units that are accessible during a first time interval in accordance with the time-based data access policy; and

identifying a second set of DS units of the plurality of DS units that are accessible during a second time interval in accordance with the time-based data access policy, wherein a number DS units in each of the first and second sets of DS units is less than the threshold number of encoded data slices.

3. The method of claim 1 further comprises:

when the threshold number of the encoded data slices have not been retrieved, generating a retrieval status message in accordance with the time-based data access policy.

4. The method of claim 1, wherein the determining the time-based data access policy is based on one or more of:

a previous time-based data access policy;

a policy schedule;

a data identifier;

the real-time indicator;

a requester identifier;

a data type;

a priority indicator;

a security indicator; and

a dispersed storage network (DSN) status indicator.

5. The method of claim 1, wherein the determining the data access policy further comprises:

adjusting the time-based data access policy based on priority of a device issuing the data retrieval request.

6. The method of claim 1, wherein the determining the time-based data access policy comprises:

extracting the time-based data access policy from the data retrieval request when priority of a device issuing the data retrieval request is at a first priority level.

7. A method comprises:

receiving a data write request from a requesting device, wherein the data write request includes data;

encoding at least a portion of the data into a set of encoded data slices in accordance with an error coding dispersal storage function;

identifying a set of dispersed storage (DS) units and a time-based data access policy based on a privilege set of the requesting device; and

outputting the set of encoded data slices to the set of DS units in accordance with the time-based data access policy.

8. The method of claim 7 further comprises:

identifying the set of DS units based on the privilege set of the requesting device; and

generating the time-based data access policy based on the set of DS units.

9. The method of claim 7 further comprises:

identifying the time-based data access policy based on the privilege set of the requesting device; and

generating the set of DS units based on the time-based data access policy.

10. The method of claim 7, wherein the identifying the set of DS units and the time-based data access policy comprises:

obtaining a real-time indicator corresponding to when the data write request was received; and

identifying the set of DS units and the time-based data access policy based on the real-time indicator.

11. The method of claim 7, wherein the identifying the set of DS units and the time-based data access policy comprises:

extracting the identifying the set of DS units and the time-based data access policy from the data write request when priority of the requesting device is at a first priority level.

12. A computer comprises:

an interface; and

a processing module operable to;

receive, via the interface, a data retrieval request;

each

obtain a real-time indicator corresponding to when the data retrieval request was received;

determine a time-based data access policy based on the data retrieval request and the real-time indicator;

access, via the interface, a plurality of dispersed storage (DS) units in accordance with the time-based data access policy to retrieve encoded data slices; and

decode the threshold number of encoded data slices in accordance with an error coding dispersal storage function when a threshold number of the encoded data slices have been retrieved.

13. The computer of claim 12, wherein the processing module further functions to access the plurality of dispersed storage (DS) units by:

identifying a first set of DS units of the plurality of DS units that are accessible during a first time interval in accordance with the time-based data access policy; and

identifying a second set of DS units of the plurality of DS units that are accessible during a second time interval in accordance with the time-based data access policy, wherein a number DS units in each of the first and second sets of DS units is less than the threshold number of encoded data slices.

14. The computer of claim 12, wherein the processing module further functions to:

generate a retrieval status message in accordance with the time-based data access policy when the threshold number of the encoded data slices have not been retrieved.

15. The computer of claim 12, wherein the processing module further functions to determine the time-based data access policy based on one or more of:

a previous time-based data access policy;

a policy schedule;

a data identifier;

the real-time indicator;

a requester identifier;

a data type;

a priority indicator;

a security indicator; and

a dispersed storage network (DSN) status indicator.

16. The computer of claim 12, wherein the processing module further functions to determine the data access policy by:

adjusting the time-based data access policy based on priority of device issuing the data retrieval request.

17. The computer of claim 12, wherein the processing module further functions to determine the time-based data access policy by:

extracting the time-based data access policy from the data retrieval request when priority of device issuing the data retrieval request is at a first priority level.

18. A computer comprises:

an interface; and

a processing module operable to;

receive, via the interface, a data write request from a requesting device, wherein the data write request includes data;

encode at least a portion of the data into a set of encoded data slices in accordance with an error coding dispersal storage function;

identify a set of dispersed storage (DS) units and a time-based data access policy based on a privilege set of the requesting device; and

output, via the interface, the set of encoded data slices to the set of DS units in accordance with the time-based data access policy.

19. The computer of claim 18, wherein the processing module further functions to:

identify the set of DS units based on the privilege set of the requesting device; and

generate the time-based data access policy based on the set of DS units.

20. The computer of claim 18, wherein the processing module further functions to:

identify the time-based data access policy based on the privilege set of the requesting device; and

generate the set of DS units based on the time-based data access policy.

21. The computer of claim 18, wherein the processing module further functions to identify the set of DS units and the time-based data access policy by:

obtaining a real-time indicator corresponding to when the data write request was received; and

identifying the set of DS units and the time-based data access policy based on the real-time indicator.

22. The computer of claim 18, wherein the processing module further functions to identify the set of DS units and the time-based data access policy by:

extracting the identifying the set of DS units and the time-based data access policy from the data write request when priority of the requesting device is at a first priority level.