FAILSAFE DIRECTORY FILE SYSTEM IN A DISPERSED STORAGE NETWORK

• US 20140229760A1
• Filed: 04/21/2014
• Published: 08/14/2014
• Est. Priority Date: 03/15/2010
• Status: Active Grant

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Gladwin, S. Christopher, Grube, Gary W., Resch, Jason K., Markison, Timothy W.
• Granted Patent: US 9,116,626 B2
• Time in Patent Office: Days
• US Class Current: 714/6.2
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 12/1425 the protection being physical, e.g. cell, word, block
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0638 Organizing or formatting or addressing of data
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources

Abstract

A file directory system comprises a directory file, a directory address for the directory file, and a directory address failsafe mechanism. The directory file includes one or more directory entries and one or more corresponding addresses for the one or more directory entries. The directory address failsafe mechanism functions to dispersed storage error encode the directory address to produce a plurality of encoded components of the directory address and transmit the plurality of encoded components of the directory address to a plurality of agent modules.

Claims

1. A computer readable memory device comprises:

a first memory section storing operational instructions that, when executed by a computing device, causes the computing device to;

receive a file access request;

a second memory section storing operational instructions that, when executed by the computing device, causes the computing device to;

identify a directory file path based on the file access request;

a third memory section storing operational instructions that, when executed by the computing device, causes the computing device to;

determine that a directory address of a directory file of the directory file path is not available; and

when the directory address is not available, determine whether to reconstruct the directory address or to use a redundant directory file path; and

a fourth memory section storing operational instructions that, when executed by the computing device, causes the computing device to;

when reconstructing the directory address;

retrieve encoded components of the directory address from a plurality of agent modules; and

when at least a threshold number of the encoded components of the directory address have been received, reconstruct the directory address from the at least a threshold number of the encoded components of the directory address.

2. The computer readable memory device of claim 1, wherein the third memory section further stores operational instructions that, when executed by the computing device, causes the computing device to:

when using the redundant directory file path, determine one or more directory addresses for one or more redundant directory files in the redundant directory file path; and

access a file via the one or more directory addresses of the redundant directory file path.

3. The computer readable memory device of claim 1, wherein the directory address comprises:

a dispersed storage network (DSN) directory address.

4. The computer readable memory device of claim 1, wherein the directory file comprises at least one of:

a root directory file;

an intermediate directory file; and

a file-level directory file.

5. The computer readable memory device of claim 1, wherein the second memory section further stores operational instructions that, when executed by the computing device, causes the computing device to identify the directory file path when the file access request is a write data request by:

determining whether the directory file path exists;

when the directory file path does not exist, creating the directory file path;

determining whether to create a redundant directory file path; and

when it is determined to create the redundant directory file path, creating the redundant directory file path.