Block data migration

• US 20040210724A1
• Filed: 01/21/2004
• Published: 10/21/2004
• Est. Priority Date: 01/21/2003
• Status: Abandoned Application

• Current Assignee: Dell Products LP (Dell Technologies Inc.)
• Original Assignee: Equallogic Incorporated (Dell Technologies Inc.)
• Inventors: Long, Paula, Hayden, Peter C., Koning, G. Paul
• Application Number:
  US10/762,984
• Publication Number:
  US 20040210724A1
• Time in Patent Office: Days
• US Class Current: 711/153
• CPC Class Codes: G06F 16/119 Details of migration of file systems migration mechanisms in storage systems G06F3/0647
• CPC Class Codes: G06F 16/1827 Management specifically adapted to NAS management of storage area networks [SAN] G06F3/067
• CPC Class Codes: G06F 3/061 Improving I/O performance
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• 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: H04L 69/329 in the application layer [OSI layer 7]

Abstract

Systems for managing responses to requests from a plurality of clients for access to a set of resources and for providing a storage area network (SAN) that more efficiently responds to client load changes by migrating data blocks while providing continuous data access. In one embodiment, the systems comprise a plurality of equivalent servers wherein the set of resources is partitioned across this plurality of servers. Each equivalent server has a load monitor process that is capable of communicating with the other load monitor processes for generating a measure of the client load on the server system and the client load on each of the respective servers. The system further comprises a resource distribution process that is responsive to the measured system load and is capable of repartitioning the set of resources to thereby redistribute the client load.

Claims

1. An apparatus for resource migration, comprising a storage system having

a plurality of storage servers with a set of resources partitioned thereon, said storage servers having a load monitor process capable of communicating with other load monitor processes for generating a measure of loading on respective ones of the plurality of servers;

a resource migration process for transferring a resource from one of said plurality of servers to another of said plurality of servers in response to said measure of loading.

2. The apparatus of claim 1, wherein said servers are equivalent to each other.

3. The apparatus of claim 1, wherein said resources are selected from the group consisting of data blocks, program files, multimedia files, applications, and database files.

4. The apparatus of claim 1, wherein said measure of loading reflects both a storage system load and a server load.

5. The apparatus of claim 1, wherein said storage system is a Storage Area Network.

6. The apparatus of claim 1, wherein the load monitor includes a process to determine whether a server is servicing a disproportionate share of the client requests being handled by a server group.

7. The apparatus of claim 1, wherein the resource migration process includes a block data migration process.

8. The apparatus of claim 1, further including a routing table for tracking resources maintained on the system.

9. The apparatus of claim 1, wherein a pointer to a resource is maintained during a an access operation to provide continuous data access.

10. The apparatus of claim 1, wherein the load monitoring process monitors one or more of network traffic load, I/O request load, storage traffic pattern type.

11. The apparatus of claim 1, wherein the resource migration process includes a further process to detect when a resource write request applies to a resource that is in the process of being moved from a first server to a second server, and apply such resource write request to both copies of the resource held at said first and said second server.

12. The apparatus of claim 1, wherein the resource migration process divides the resource being moved into smaller subresources, such that each subresource is moved from a first server to a second server in turn, and recovery from failure requires only the recovery of the subresource being moved at the time of failure and subsequent subresources.

13. The apparatus of claim 12, wherein the resource migration process includes a further process to detect when a resource write request applies to a subresource that is in the process of being moved from a first server to a second server, and apply such resource write request to both copies of the resource held at said first and said second server.

14. A process for moving resources across a storage system having

a plurality of storage servers with a set of resources partitioned thereon, comprising the steps of

monitoring a load on a server and communicating with other load monitor processes for generating a measure of loading on respective ones of the plurality of servers;

and

transferring, as a function of the measured loads, a resource from one of said plurality of servers to another of said plurality of servers in response to said measure of loading.

15. The process of claim 14, wherein said servers are equivalent to each other.

16. The process of claim 14, measuring a load includes measuring a storage system load and a server load.

17. The process of claim 14, including the further step determining whether a server is servicing a disproportionate share of the client requests being handled by a server group.

18. The process of claim 14, wherein the resource migration process includes a block data migration process.

19. The process of claim 14, further including maintaining a routing table for tracking resources maintained on the system.

20. The process of claim 14, wherein the load monitoring process monitors one or more of network traffic load, I/O request load, storage traffic pattern type.

21. The process of claim 14, further including maintaining a pointer to a resource is maintained during an access operation to provide continuous data access.

22. The process of claim 14, further including detecting when a resource write request applies to a resource that is in the process of being moved from a first server to a second server, and applying such resource write request to both copies of the resource held at said first and said second server.

23. The process of claim 14, further including dividing the resource being moved into smaller subresources, such that each subresource is moved from a first server to a second server in turn, and recovery from failure requires only the recovery of the subresource being moved at the time of failure and subsequent subresources.

24. The process of claim 23, further including detecting when a resource write request applies to a subresource that is in the process of being moved from a first server to a second server, and apply such resource write request to both copies of the resource held at said first and said second server. server to a second server, and apply such resource write request to both copies of the resource held at said first and said second server.