Data migration

A storage controller for a data processing system comprising:

• a host processor and local physical storage, the storage controller performing the actions of:
• defining a virtual storage volume for access by the host processor, wherein the storage controller includes a local storage pool mapped to the local physical storage and a remote storage pool mapped to physical storage at a remote site, and wherein the virtual storage volume is overallocated from the local storage pool;
• and
• migrating data between the local storage pool and the remote storage pool according to a defined migration policy.

A computer system, comprising:

• a host processor, physical storage and a storage controller located in the data path between the processor and storage, the storage controller being operable to perform the actions of:
• defining a virtual storage volume for access by the host processor, wherein a local storage pool is mapped to the local physical storage and a remote storage pool is mapped to physical storage at a remote site, and wherein the virtual storage volume is overallocated from the local storage pool;
• and
• migrating data between the local storage pool and the remote storage pool according to a defined migration policy.

A computer network, comprising:

• a local data processing system, including a host processor, physical storage and a storage controller;
• and
• a remote data processing system, comprising remote physical storage;
• wherein the storage controller is operable to perform the actions of:
• defining a virtual storage volume for access by the host processor, including mapping a local storage pool to the local physical storage and mapping a remote storage pool to the remote physical storage, the virtual storage volume being overallocated from the local storage pool;
• and
• migrating data between the local storage pool and the remote storage pool according to a defined migration policy.