Logical volume-level migration in a partition-based distributed file system

• US 6,775,673 B2
• Filed: 12/19/2001
• Issued: 08/10/2004
• Est. Priority Date: 12/19/2001
• Status: Expired due to Fees

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Zhang, Zheng, Mahalingam, Mallik, Karamanolis, Christos, Muntz, Daniel A.
• Primary Examiner(s): Mizrahi, Diane D.
• Assistant Examiner(s): Mofiz, Apu M
• Application Number:
  US10/024,941
• Publication Number:
  US 20030115434A1
• Time in Patent Office: 965 Days
• Field of Search: 707/4, 707/10, 707/100, 707/102, 707/103.R, 707/104.1, 707/205, 709/203, 709/234, 709/235, 709/238, 709/245, 709/248, 710/74, 715/500.1, 717/102, 717/109, 711/120
• US Class Current: 1/1
• CPC Class Codes: G06F 16/10 File systems; File servers
• CPC Class Codes: G06F 3/0607 by facilitating the process of upgrading existing storage systems, e.g. for improving compatibility between host and storage device
• CPC Class Codes: G06F 3/0643 Management of files
• CPC Class Codes: G06F 3/0647 Migration 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: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• 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: Y10S 707/99953 Recoverability

Abstract

Method and system for migrating a logical volumes in a distributed file system having multiple partitions servers. Each partition server owns one or more volumes, and each volume including a subset of logically related objects of the file system. In response to a migration request that requests migration of a selected logical volume from a source partition server to the target partition server, an ownership map is updated to indicate the selected logical volume is owned by the target partition server. At the source partition server, forwarding information is stored to reference the target partition server. When the source partition server receives a request for access to the object, the forwarding information is transmitted to the requester.

Claims

1. A computer-implemented method for migrating a logical volume of objects from a source partition server to a target partition server in a distributed file system having multiple partitions servers, wherein each partition server owns one or more volumes, each volume including a subset of logically related objects of the file system, comprising:

updating, in response to a migration request that requests migration of a selected logical volume from a source partition server to the target partition server, an ownership map to indicate the selected logical volume is owned by the target partition server;

storing at the source partition server forwarding information that references the target partition server; and

transmitting the forwarding information to a requester in response to an access request received at the source partition server for an object in the selected logical volume.

2. The method of claim 1, further comprising returning the forwarding information in the source partition server to free space in the file system after a selected period of time.

3. The method of claim 1, further comprising maintaining a centralized ownership map, the centralized ownership map including associations between logical-volume identifiers of logical volumes and the partition servers that own the logical volumes.

4. The method of claim 3, further comprising transmitting the forwarding information to the client in response to an access request received at the source partition server from a client for an object in the selected logical volume.

5. The method of claim 1, further comprising maintaining a distributed ownership map in the partition servers, each partition server having a portion of the ownership map that includes logical-volume identifiers of logical volumes owned by the partition server.

6. The method of claim 5, further comprising transmitting the forwarding information to the client in response to an access request received at the source partition server from a client for an object in the selected logical volume.

7. The method of claim 1, further comprising:

queueing requests for access to objects in the selected volume before updating the ownership map; and

transmitting the forwarding information to requesters of the queued requests after the forwarding information has been stored.

8. The method of claim 7, further comprising maintaining a centralized ownership map, the centralized ownership map including associations between logical-volume identifiers of logical volumes and the partition servers that own the logical volumes.

9. The method of claim 8, further comprising transmitting the forwarding information to the client in response to an access request received at the source partition server from a client for an object in the selected logical volume.

10. The method of claim 7, further comprising maintaining a distributed ownership map in the partition servers, each partition server having a portion of the ownership map that includes logical-volume identifiers of logical volumes owned by the partition server.

11. The method of claim 10, further comprising transmitting the forwarding information to the client in response to an access request received at the source partition server from a client for an object in the selected logical volume.

12. An apparatus for migrating a logical volume of objects from a source partition server to a target partition server in a distributed file system having multiple partitions servers, wherein each partition server owns one or more volumes, each volume including a subset of logically related objects of the file system, comprising:

means, responsive to a migration request that requests migration of a selected logical volume from a source partition server to the target partition server, for updating an ownership map to indicate the selected logical volume is owned by the target partition server;

means for storing at the source partition server forwarding information that references the target partition server; and

means for transmitting the forwarding information to the client in response to an access request received at the source partition server from a client for an object in the selected logical volume.

13. A computer-readable medium configured with computer program code for migrating a logical volume of objects from a source partition server to a target partition server in a distributed file system having multiple partitions servers, wherein each partition server owns one or more volumes, each volume including a subset of logically related objects of the file system, the computer program code configured to cause a computer to perform the steps comprising:

updating, in response to a migration request that requests migration of a selected logical volume from a source partition server to the target partition server, an ownership map to indicate the selected logical volume is owned by the target partition server;

storing at the source partition server forwarding information that references the target partition server; and

transmitting the forwarding information to the client in response to an access request received at the source partition server from a client for an object in the selected logical volume.

14. A distributed file management system, comprising:

a plurality of partition servers configured for ownership of a set of logical volumes of logically related file system objects, each partition server configured to control access to the set of logical volumes owned by the partition server;

an ownership map coupled to the plurality of partition servers, the ownership map indicating which partition servers own which logical volumes; and

wherein each partition server is adapted to migrate a selected logical volume from a source partition server to a target partition server in response to a migration request.

15. The system of claim 14, wherein each partition server is configured to store, in response to being the source partition server in the migration request, forwarding information that references the target partition server, and transmit the forwarding information to requesters that reference objects of the selected logical volume.

16. The system of claim 14, further comprising a storage manager coupled to the partition servers, the storage manager configured to maintain a the ownership map that includes associations between logical-volume identifiers of logical volumes and the partition servers that own the logical volumes.

17. The system of claim 14, wherein each partition server maintains a portion of the ownership map that includes logical-volume identifiers of logical volumes owned by the partition server.