Techniques for Migrating Active I/O Connections with Migrating Servers and Clients

1 . A method for modifying an input/output (I/O) connection type between a client and a server, comprising:

determining, by a client, when at least partial storage access control for the client is to be migrated from a first virtualized I/O server to a second virtualized I/O server;

selecting, by the client, an I/O connection type from among multiple available I/O connection types available between the client and the second virtualized I/O server when the at least partial storage access control for the client is to be migrated; and

communicating, by the client, the selected I/O connection type to the second virtualized I/O server, wherein the second virtualized I/O server is configured to facilitate storage access for the client using the selected I/O connection type.

2 . The method of claim 1 , wherein the second virtualized I/O server is a replica of the first virtualized I/O server and the method further comprises:

accessing, by the client, storage via both the first and second virtualized I/O servers.

3 . The method of claim 1 , wherein the second virtualized I/O server resides on a different virtual host than the first virtualized I/O server and the second virtualized I/O server is further configured to facilitate storage access for the client during and following migration of the at least partial storage access control from the first virtualized I/O server to the second virtualized I/O server.

4 . The method of claim 1 , wherein the client includes a cluster of clients and each of the clients in the cluster is configured to select respective I/O connection types in conjunction with the other clients to balance a load on the second virtualized I/O server.

5 . The method of claim 1 , wherein the I/O connection type is a Fibre Channel connection, a small computer system interface (SCSI) connection, an Internet SCSI connection, or an InfiniBand connection.

6 . The method of claim 1 , wherein the first and second virtualized I/O servers are located in a same storage area network and the second virtualized I/O server is further configured to facilitate storage access for the client following migration of the at least partial storage access control from the first virtualized I/O server to the second virtualized I/O server.

7 . The method of claim 1 , wherein the selecting, by the client, an I/O connection type from among multiple available I/O connection types available between the client and the second virtualized I/O server further comprises:

testing, by the client, each of the multiple available I/O connection types to determine a performance level of each of the multiple available I/O connection types; and

selecting, by the client, the I/O connection type based on which of the multiple available I/O connection types yields a highest performance level, as indicated by the testing, and allows a connection between the client and the second virtualized I/O server to be maintained.

8 . The method of claim 1 , wherein the client is included in a client cluster that includes at least one other client, and wherein storage access control for the at least one other client remains under control of the first virtualized I/O server to substantially balance a load for the client cluster between the first and second virtualized I/O servers, where I/O connection types for clients in the client cluster may be the same or different.

9 . The method of claim 1 , wherein the client queries the second virtualized I/O server to determine the multiple available I/O connection types.

10 . The method of claim 1 , wherein the second virtualized I/O server is a replica of the first virtualized I/O server that is migrated to a new virtual host.

11 . A computer-readable storage medium including computer-readable code for modifying an input/output (I/O) connection type between a client and a server, the computer-readable code comprising:

code for determining, by a client, when at least partial storage access control for the client is to be migrated from a first virtualized I/O server to a second virtualized I/O server;

code for selecting, by the client, an I/O connection type from among multiple available I/O connection types available between the client and the second virtualized I/O server when the at least partial storage access control for the client is to be migrated; and

code for communicating, by the client, the selected I/O connection type to the second virtualized I/O server, wherein the second virtualized I/O server is configured to facilitate storage access for the client using the selected I/O connection type.

12 . The computer-readable storage medium of claim 11 , wherein the second virtualized I/O server is a replica of the first virtualized I/O server and the code further comprises:

code for accessing, by the client, storage via both the first and second virtualized I/O servers.

13 . The computer-readable storage medium of claim 11 , wherein the second virtualized I/O server resides on a different virtual host than the first virtualized I/O server and the second virtualized I/O server is further configured to facilitate storage access for the client during and following migration of the at least partial storage access control from the first virtualized I/O server to the second virtualized I/O server.

14 . The computer-readable storage medium of claim 11 , wherein the client includes a cluster of clients and each of the clients in the cluster is configured to select respective I/O connection types in conjunction with the other clients to balance a load on the second virtualized I/O server, and wherein the I/O connection types include a Fibre Channel connection, a small computer system interface (SCSI) connection, an Internet SCSI connection, and an InfiniBand connection.

15 . The computer-readable storage medium of claim 11 , wherein the first and second virtualized I/O servers are located in a same storage area network and the second virtualized I/O server is further configured to facilitate storage access for the client following migration of the at least partial storage access control from the first virtualized I/O server to the second virtualized I/O server.

16 . The computer-readable storage medium of claim 11 , wherein the code for selecting an I/O connection type, from among multiple available I/O connection types, available between the client and the second virtualized I/O server further comprises:

code for testing, by the client, each of the multiple available I/O connection types to determine a performance level of each of the multiple available I/O connection types; and

code for selecting, by the client, the I/O connection type based on which of the multiple available I/O connection types yields a highest performance level, as indicated by the testing, and allows a connection between the client and the second virtualized I/O server to be maintained.

17 . The computer-readable storage medium of claim 11 , wherein the client is included in a client cluster that includes at least one other client and storage access control for the at least one other client remains under control of the first virtualized I/O server to substantially balance a load for the client cluster between the first and second virtualized I/O servers, and wherein the client queries the second virtualized I/O server to determine the multiple available I/O connection types, where I/O connection types for clients in the client cluster may be the same or different.

18 . A data processing system, comprising:

a first virtualized server configured to facilitate storage access control;

a client configured to select an I/O connection type, from among multiple available I/O connection types, when at least partial storage access control for the client is migrated from the first virtualized server; and

a second virtualized I/O server configured to transmit the multiple available I/O connection types to the client in response to a query from the client, wherein the second virtualized I/O server is further configured to facilitate storage access control for the client during and following migration of the at least partial storage access control from the first virtualized I/O server to the second virtualized I/O server.

19 . The data processing system of claim 18 , wherein the client is further configured to test each of the multiple available I/O connection types to determine a performance level of each of the multiple available I/O connection types and select the I/O connection type based on which of the multiple available I/O connection types yields a highest performance level, as indicated by the testing, and allows a connection between the client and the second virtualized I/O server to be maintained.

20 . The data processing system of claim 18 , wherein the client is included in a client cluster that includes at least one other client and storage access control for the at least one other client remains under control of the first virtualized I/O server to substantially balance a load for the client cluster between the first and second virtualized I/O servers, and wherein the client queries the second virtualized I/O server to determine the multiple available I/O connection types, where I/O connection types for clients in the client cluster may be the same or different.