Patent ID: 9400611
Filing Date: 2016-07-26
CPC Classification: G06F,H04L

Claim Text:
1. A method of migrating data from a source LUN to a target LUN in a data processing system having a cluster of multiple host computers and a storage subsystem containing the source LUN and the target LUN, the data being accessed concurrently by applications of the host computers using an association mechanism in each of the host computers initially associating the data with the source LUN as the location of the data in the system, comprising: performing a synchronization as iterations of concurrent operations at the host computers, a first iteration including a copy sweep by a first host computer to copy all existing data blocks of the source LUN to the target LUN, the first iteration and each subsequent iteration including at each of second host computers recording the locations of data blocks changed by application writes to the source LUN, the recording employing a respective changed-block record of the respective second host computer, each subsequent iteration also including, for each data block location identified in the changed-block record of each of the second host computers for the preceding iteration, copying the corresponding data blocks of the source LUN to the target LUN; and upon completion of the synchronization, performing a commitment including a final iteration and a transition to operation with the target LUN, the final iteration including, for a final set of recorded locations of data blocks in the changed-block record of each of the second host computers, copying the corresponding data blocks of the source LUN to the target LUN, the transition including at each host computer disabling application access to the source LUN and modifying the association mechanism to newly associate the data with the target LUN as the location of the data in the system.