Patent ID: 8706960

Claim:
A computer implemented method for performing data migration in a data storage system comprising: identifying a source logical volume of the data storage system, said source logical volume having at least a first mirror mapped to first storage; identifying a target included in the data storage system, wherein if the target is unconfigured storage of the data storage system, the target is mapped as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target, and if the target is configured storage of another logical volume of the data storage system, the configured storage is remapped as storage for another mirror of the source logical volume prior to copying data from the source logical volume to the target; setting one or more invalid bits indicating that the target does not contain a valid copy of data from the source logical volume; copying data from the first mirror of the source logical volume to the target and clearing one or more invalid bits as one or more data portions of the first mirror of the source logical volume corresponding to said one or more invalid bits are copied to the target, wherein storage for the first mirror of the source logical volume is included in a first RAID group and storage for the target mapped as a second mirror of the source logical volume is included in a second RAID group having a different RAID level than the first RAID group; and after the one or more invalid bits have been cleared thereby indicating completion of copying data from the first mirror of the source logical volume to the target, performing processing, said processing including: reinitializing the first storage mapped to the first mirror of the source logical volume; and unmapping the first storage from the first mirror of the source logical volume.