Patent ID: 8301811

Claim:
A method of migrating data from a storage device of a source array to a storage device of a target array while preserving small computer system interface (SCSI) reservation compliance, each storage device being capable of operating in (i) an active mode in which that storage device is permitted to perform host read and write operations and (ii) a passive mode in which that storage device is not permitted to perform host read and write operations, the method comprising: while a first SCSI reservation exists which enables a set of hosts to access host data on the storage device of the source array using multipath I/O software, providing an active-to-passive instruction to the source array, the active-to-passive instruction directing the source array to (i) transition the storage device of the source array from the active mode to the passive mode and (ii) upon receipt of a next SCSI instruction sent from the set of hosts to the storage device of the source array, output a source response to the set of hosts, the source response having a reservation cleared indicator indicating that the first SCSI reservation has been cleared on the source array; after the storage device of the source array transitions from the active mode to the passive mode, transitioning the storage device of the target array from the passive mode to the active mode and beginning a data transfer operation which transfers data from the storage device of the source array to the storage device of the target array; and after the storage device of the target array transitions from the passive mode to the active mode, establishing a second SCSI reservation in place of the first SCSI reservation, the second SCSI reservation enabling the set of hosts to access the host data on the storage device of the target array using the multipath I/O software.