Method, system and program for storing and using metadata in multiple storage locations

• US 8,001,104 B2
• Filed: 08/19/2008
• Issued: 08/16/2011
• Est. Priority Date: 11/17/2004
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Frondozo, Rhea Reyes, Sheppard, Jacob Lee, Lovrien, Kurt Allen, Ripberger, Richard Anthony, Vageline, Michael P.
• Primary Examiner(s): Wong; Don
• Assistant Examiner(s): Nguyen; Kim T
• Application Number:
  US12/194,357
• Publication Number:
  US 20080313416A1
• Time in Patent Office: 1,092 Days
• Field of Search: 707/706, 707/821
• US Class Current: 707/706
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata
• CPC Class Codes: G06F 11/2056 by mirroring
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality
• CPC Class Codes: G06F 11/2094 Redundant storage or storage space G06F11/2056 takes precedence
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 3/0614 Improving the reliability of storage systems
• CPC Class Codes: G06F 3/065 Replication mechanisms
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users

Abstract

Provided are a method, system, and program for storing and using metadata in multiple storage location. Signature data is stored in a system storage indicating a plurality of metadata copy locations, each locating identifying a storage device and a copy location within the storage device. Each location contains one copy of the metadata, wherein the metadata includes system configuration information. A copy of the signature data is stored with each copy of the metadata.

Claims

1. A method, comprising:

generating signature data indicating a plurality of metadata copy locations, each metadata copy location identifying one of a plurality of storage devices and a copy location within the storage device, wherein each copy location contains one copy of the metadata, wherein the metadata includes system configuration information;

storing a copy of the signature data with copies of the metadata in the storage devices indicated in the metadata copy locations of the signature data;

using the signature data to determine a copy location of valid metadata;

reading one copy of the valid metadata from the determined copy location in one of the storage devices to obtain system configuration information from the valid metadata to use to operate;

initiating an operation to alter the copy locations of the metadata copies in the storage devices storing the metadata;

determining new copy locations in the storage devices for the metadata;

updating each copy location of the signature data to indicate the new copy locations for the metadata; and

copying metadata and the updated signature data to any of the new copy locations that do not already include metadata and signature data.

2. The method of claim 1, wherein the location of the storage devices to store the copies of the metadata are selected to minimize a number of points of failure.

3. The method of claim 1, wherein the metadata copy locations indicated in the signature data comprise an ordered set, wherein the signature data is updated at the copy locations in an order according to the ordered set.

4. The method of claim 1, wherein the determination of the new copy locations is made in response to a change in the set of storage devices and wherein the determination of the new copy locations is performed in order to minimize a number of points of failure for the changed set of the storage devices.

5. The method of claim 1, wherein two processing systems are capable of accessing the metadata and the signature data in the storage devices, and wherein each processing system has a computer readable medium including a copy of the signature data.

6. The method of claim 5, further comprising:

receiving an update to the metadata; and

serially copying the update to the metadata in the storage devices according to an ordering of the copy locations indicated in the signature data.

7. The method of claim 5, further comprising:

receiving a request to read the metadata;

accessing the metadata in the copy locations until one valid copy of the metadata is found; and

updating copies of the metadata determined to be invalid with the accessed valid copy of the metadata.

8. A system, comprising:

a plurality of storage devices;

a processing system having a system storage and in communication with the storage devices; and

a computer readable medium including code executed by the processing system to perform operations comprising;

generating signature data indicating a plurality of metadata copy locations, each metadata copy location identifying one of a plurality of storage devices and a copy location within the storage device, wherein each copy location contains one copy of the metadata, wherein the metadata includes system configuration information;

storing a copy of the signature data with copies of the metadata in the storage devices indicated in the metadata copy locations of the signature data;

using the signature data to determine a copy location of valid metadata;

reading one copy of the valid metadata from the determined copy location in one of the storage devices to obtain system configuration information from the valid metadata to use to operate;

initiating an operation to alter the copy locations of the metadata copies in the storage devices storing the metadata;

determining new copy locations in the storage devices for the metadata;

updating each copy location of the signature data to indicate the new copy locations for the metadata; and

copying metadata and the updated signature data to any of the new copy locations that do not already include metadata and signature data.

9. The system of claim 8, wherein the locations of the storage devices to store the copies of the metadata are selected to minimize a number of points of failure.

10. The system of claim 8, wherein the copy locations within the signature data comprises an ordered set, wherein the signature data is updated at the copy locations in an order according to the ordered set.

11. The system of claim 10, wherein the determination of the new copy location is made in response to a change in the set of storage devices and wherein the determination of the new location is performed in order to minimize a number of points of failure for the changed set of the storage devices.

12. The system of claim 8, wherein the processing system comprises a first processing system, further comprising:

a second processing system, wherein both processing systems are capable of accessing the metadata and the signature data in the storage devices, and wherein each processing system has a local storage including a copy of the signature data.

13. The system of claim 12, wherein the code further causes operations comprising:

receiving an update to the metadata; and

serially copying the update to the metadata in the storage devices according to an ordering of the copy locations indicated in the signature data.

14. The system of claim 12, wherein the code further causes operations comprising:

receiving a request to read the metadata;

accessing the metadata in the copy locations until one valid copy of the metadata is found; and

updating copies of the metadata determined to be invalid with the accessed valid copy of the metadata.

15. An article of manufacture comprising at least one of a hardware device having hardware logic and a computer readable storage medium having executable code to communicate with a plurality of storage devices and a system storage and to cause operations to be performed, the operations comprising:

generating signature data indicating a plurality of metadata copy locations, each metadata copy location identifying one of a plurality of storage devices and a copy location within the storage device, wherein each copy location contains one copy of the metadata, wherein the metadata includes system configuration information;

storing a copy of the signature data with copies of the metadata in the storage devices indicated in the metadata copy locations of the signature data;

using the signature data to determine a copy location of valid metadata;

reading one copy of the valid metadata from the determined copy location in one of the storage devices to obtain system configuration information from the valid metadata to use to operate;

initiating an operation to alter the copy locations of the metadata copies in the storage devices storing the metadata;

determining new copy locations in the storage devices for the metadata;

updating each copy location of the signature data to indicate the new copy locations for the metadata; and

copying metadata and the updated signature data to any of the new copy locations that do not already include metadata and signature data.

16. The article of manufacture of claim 15, wherein the location of the storage devices to store the copies of the metadata are selected to minimize a number of points of failure.

17. The article of manufacture of claim 15, wherein the copy locations within the signature data comprises an ordered set, wherein the signature data is updated at the copy locations in an order according to the ordered set.

18. The article of manufacture of claim 15, wherein the determination of the new copy location is made in response to a change in the set of storage devices and wherein the determination of the new copy location is performed in order to minimize a number of points of failure for the changed set of the storage devices.

19. The article of manufacture of claim 15, wherein two processing systems are capable of accessing the metadata and the signature data in the storage devices, and wherein each processing system has a computer readable medium including a copy of the signature data.

20. The article of manufacture of claim 19, wherein the operations further comprise:

receiving an update to the metadata; and

serially copying the update to the metadata in the storage devices according to an ordering of the copy locations indicated in the signature data.

21. The article of manufacture of claim 19, wherein the operations further comprise:

receiving a request to read the metadata;

accessing the metadata in the copy locations until one valid copy of the metadata is found; and

updating copies of the metadata determined to be invalid with the accessed valid copy of the metadata.