Online migration of a logical volume between storage systems

A storage facility, comprising:

• a storage area network (SAN);
• a host computer configured on the SAN;
• a target storage system having target regions and configured on the SAN;
• and
• a source storage system having source regions, and configured on the SAN, and arranged:
• to configure a logical volume to comprise the source regions having a mapping between the host computer and the source storage system, the source regions storing source data;
• to copy the source data from the source regions to target data in the target regions, the target regions being in a one-to-one correspondence with the source regions;
• to reconfigure the logical volume so that the target regions have the mapping between the host computer and the source storage system;
• to receive a request to store an update to the one of the source regions, to store the update to the one of the source regions, and to store the update to the corresponding target region;
• and
• to copy attributes and run-time information for the logical volume from the source storage system to the target storage system, and to delete the source data.

A computer program product, the computer program product comprising:

• a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising:
• computer readable program code arranged to configure a logical volume to comprise source regions of a source storage system having a mapping between a host computer and the source storage system, the source regions storing source data;
• computer readable program code arranged to copy the source data from the source regions to target data in target regions of a target storage system, the target regions being in a one-to-one correspondence with the source regions;
• computer readable program code arranged to reconfigure the logical volume so that the target regions have the mapping between the host computer and the source storage system;
• computer readable program code arranged to receive a request to store an update to the one of the source regions, to store the update to the one of the source regions, and to store the update to the corresponding target region;
• and
• computer readable program code arranged to receive a request to store an update to the one of the source regions, to store the update to the one of the source regions, and to store the update to the corresponding target region.