Patent ID: 8006054
Filing Date: 2011-08-23
Classification: G06F

Abstract:
1. A storage system, which comprises a first storage controller and a second storage controller, the first storage controller comprising: a first volume, which is used by a host computer; a first pool volume; a first snapshot controller, which: providing a first snapshot volume and a second snapshot volume to the host computer, the first snapshot volume logically storing the storage contents of the first volume at a first point in time, the second snapshot volume logically storing the storage contents of the first volume at second point in time, the second point in time is later than the first point in time; saving update-targeted data and an update location of the first volume in the first pool volume when the first volume is updated; and relating saved update-targeted data and update location to the first snapshot volume and the second snapshot volume, the second storage controller comprising: a second volume; a second pool volume; and a second snapshot controller, which: providing at least one snapshot volume which logically storing the storage contents of the first volume at a point in time to the host computer; saving update-targeted data and an update location in the second volume in the second pool volume when the second volume is updated; and relating saved update-targeted data and update location to the at least one snapshot volume, the storage system further comprising: a migration controller for migrating data and a snapshot-related configuration from the first storage controller to the second storage controller, the migration controller configured to: generate a third snapshot volume corresponding to the first snapshot volume and a forth snapshot volume corresponding to the second snapshot volume; detect difference data between the contents of the first snapshot volume and content of the present first volume; send the contents of the first snapshot volume from the first storage controller to the second storage controller as an update request to the second volume, the contents of the first snapshot volume provided with the data stored in the first volume and detected difference data stored in the first pool volume; detect difference data between the contents of the second snapshot volume and the content of the first snapshot volume; send the detected difference data between the contents of the second snapshot volume and the content of the first snapshot volume from the first storage controller to the second storage controller as an update request to the second volume, while the status between the second volume and the third snapshot volume is suspend status and the status between the second volume and the forth snapshot volume is pair status, so that the update-targeted data and the update location in the second volume to be saved in the second pool volume by the second snapshot controller in response to the update of the second logical volume with the difference data between the contents of the second snapshot volume and the content of the first snapshot volume sent from the first storage is not related to the forth snapshot volume but the third snapshot volume.