Localized dispersed storage memory system

• US 8,527,807 B2
• Filed: 07/28/2010
• Issued: 09/03/2013
• Est. Priority Date: 11/25/2009
• Status: Expired due to Fees

• Current Assignee: Pure Storage, Inc.
• Original Assignee: Cleversafe Incorporated (International Business Machines Corporation)
• Inventors: Gladwin, S. Christopher, Grube, Gary W., Markison, Timothy W.
• Primary Examiner(s): Baderman, Scott
• Assistant Examiner(s): BRYAN, JASON B
• Application Number:
  US12/845,590
• Publication Number:
  US 20110122523A1
• Time in Patent Office: 1,133 Days
• Field of Search: None
• US Class Current: 714/6.22
• CPC Class Codes: G06F 11/1076 Parity data used in redundant arrays of independent storages, e.g. in RAID systems
• CPC Class Codes: G06F 11/1092 Rebuilding, e.g. when physically replacing a failing disk
• CPC Class Codes: G06F 2211/1092 Single disk raid, i.e. RAID with parity on a single disk
• CPC Class Codes: G06F 3/0616 in relation to life time, e.g. increasing Mean Time Between Failures [MTBF]
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: G11B 20/1252 for discontinuous data, e.g. digital information signals, computer programme data
• CPC Class Codes: G11B 20/1803 by redundancy in data representation
• CPC Class Codes: G11B 20/1889 with discs
• CPC Class Codes: G11B 5/09 Digital recording

Abstract

A method begins by a processing module receiving data to store and determining error coding dispersal storage function parameters. The method continues with the processing module encoding at least a portion of the data in accordance with the error coding dispersal storage function parameters to produce a set of data slices. The method continues with the processing module defining addressable storage sectors within the single hard drive based on a number of data slices within the set of data slices to produce a set of addressable storage sectors. The method continues with the processing module storing data slices of the set of data slices in corresponding addressable storage sectors of the set of addressable storage sectors.

Claims

1. A method for rebuilding data stored on a single hard drive, the method comprises:

detecting a storage error of an encoded data slice of a set of encoded data slices, wherein the set of encoded data slices represents data encoded using an error coding dispersal storage function, wherein the single hard drive is defined to have a set of addressable storage sectors, wherein encoded data slices of the set of encoded data slices are stored in addressable locations of corresponding addressable storage sectors of the set of addressable storage sectors, and wherein the encoded data slice having the storage error is stored at a first addressable location of a first addressable storage sector of the corresponding addressable storage sectors;

determining a type of error for the storage error; and

when the type of error is a first error type;

rebuilding the encoded data slice in accordance with the error coding dispersal storage function to produce a rebuilt encoded data slice; and

storing the rebuilt encoded data slice at a second addressable location in the first addressable storage sector

when the type of error is a second error type;

determining a second error coding dispersal storage function;

re-encoding the set of encoded data slices based on the second error coding dispersal storage function to produce a re-encoded set of encoded data slices;

re-defining addressable storage sectors of the single hard drive in accordance with the second error coding dispersal storage function and an error profile of the single hard drive to produce a re-defined set of addressable storage sectors; and

storing the re-encoded set of encoded data slices in corresponding addressable storage sectors of the re-defined set of addressable storage sectors.

2. The method of claim 1 further comprises:

updating an error profile based on the storage error.

3. The method of claim 1, wherein the determining the type of error comprises:

determining an error profile;

evaluating the error profile to determine a level of reliability;

when the level of reliability is less than or equal to a first reliability threshold, determining the first error type; and

when the level of reliability is greater than the first reliability threshold, determining the second error type.

4. The method of claim 1 further comprises:

detecting a plurality of storage errors;

determining a rate of increase of the plurality of storage errors;

evaluating the rate of increase of the plurality of storage errors to determine a level of reliability; and

when the level of reliability is greater than a reliability threshold;

determining the second error type when a size of useable storage space is greater than a storage threshold.

5. The method of claim 1 further comprises:

detecting a storage error of an encoded data slice of a plurality of sets of encoded data slices, wherein the plurality of sets of encoded data slices represents a plurality of data segments each encoded using the error coding dispersal storage function,

wherein a first encoded data slice of each of the plurality of sets of encoded data slices is stored in a first addressable storage sector of the set of addressable storage sectors, and wherein a second encoded data slice of each of the plurality of sets of encoded data slices is stored in a second addressable storage sector of the set of addressable storage sectors.

6. The method of claim 1 further comprises:

generating an initial error profile based on;

generating test data;

storing the test data in two or more storage sectors of the set of addressable storage sectors;

retrieving the test data from the two or more storage sectors of the set of addressable storage sectors to produce retrieved test data;

comparing the retrieved test data to the test data; and

when the retrieved test data does not substantially match the test data, detecting a storage error.

7. A computer comprises:

a hard drive; and

a processing module operable to;

detect a storage error of an encoded data slice of a set of encoded data slices, wherein the set of encoded data slices represents data encoded using an error coding dispersal storage function, wherein the hard drive is defined to have a set of addressable storage sectors, wherein encoded data slices of the set of encoded data slices are stored in addressable locations of corresponding addressable storage sectors of the set of addressable storage sectors, and wherein the encoded data slice having the storage error is stored at a first addressable location of a first addressable storage sector of the corresponding addressable storage sectors;

determine a type of error for the storage error; and

when the type of error is a first error type;

rebuild the encoded data slice in accordance with the error coding dispersal storage function to produce a rebuilt encoded data slice; and

store the rebuilt encoded data slice at a second addressable location in the first addressable storage sector

when the type of error is a second error type;

determine a second error coding dispersal storage function;

re-encode the set of encoded data slices based on the second error coding dispersal storage function to produce a re-encoded set of encoded data slices;

re-define addressable storage sectors of the hard drive in accordance with the second error coding dispersal storage function and an error profile of the hard drive to produce a re-defined set of addressable storage sectors; and

store the re-encoded set of encoded data slices in corresponding addressable storage sectors of the re-defined set of addressable storage sectors.

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

update an error profile based on the storage error.

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

determining an error profile;

evaluating the error profile to determine a level of reliability;

when the level of reliability is less than or equal to a first reliability threshold, determining the first error type; and

when the level of reliability is greater than the first reliability threshold, determining the second error type.

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

detect a plurality of storage errors;

determine a rate of increase of the plurality of storage errors;

evaluate the rate of increase of the plurality of storage errors to determine a level of reliability; and

when the level of reliability is greater than a reliability threshold;

determine the second error type when a size of useable storage space is greater than a storage threshold.

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

detect a storage error of an encoded data slice of a plurality of sets of encoded data slices,

wherein the plurality of sets of encoded data slices represents a plurality of data segments each encoded using the error coding dispersal storage function, wherein a first encoded data slice of each of the plurality of sets of encoded data slices is stored in a first addressable storage sector of the set of addressable storage sectors, and wherein a second encoded data slice of each of the plurality of sets of encoded data slices is stored in a second addressable storage sector of the set of addressable storage sectors.

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

generate an initial error profile based on;

generating test data;

storing the test data in two or more storage sectors of the set of addressable storage sectors;

retrieving the test data from the two or more storage sectors of the set of addressable storage sectors to produce retrieved test data;

comparing the retrieved test data to the test data; and

when the retrieved test data does not substantially match the test data, detecting a storage error.