Patent ID: 8700870
Filing Date: 2014-04-15
Classification: G06F,H04L

Abstract:
1. A volume migration method with a storage system comprising: an external storage device providing at least one external volume by a plurality of external physical storage devices; a first storage device coupled to the external storage device and providing a first virtual volume and second virtual volume each of which is mapped to one of a plurality of the external volume; a second storage device coupled to the external storage device, wherein the external storage device is external to the first and second storage devices; and providing a third virtual volume and fourth virtual volume; wherein the volume migration method includes: splitting a copy pair between the first virtual volume and the second virtual volume during a copy from the first virtual volume to the second virtual volume, migrating a configuration information which indicates the external volume which is mapped to the first virtual volume and the second virtual volume from the first storage device to the second device; setting the migrated configuration information to the third virtual volume and the fourth virtual volume to which the first virtual volume and second virtual volume are migrated; copying a first differential information which indicates difference between the first virtual volume and the second virtual volume to a second differential information for the third volume and the fourth virtual volume managed in the second storage device; responding to an I/O request from a computer to the migrated virtual volume pair by referring to the second differential information managed in the second storage device, if the copying of the first differential information for data the I/O requested is complete, and responding to an I/O request from the computer to the migrated virtual volume by referring to the first differential information managed in the first storage system device if the copying of the first differential information for data the I/O requested is not completed.