Patent ID: 6976139
Filing Date: 2005-12-13
Classification: G06F,Y10S

Abstract:
1. A method of reversing a communication path between a first volume on a first storage device and a second volume on a second storage device, comprising: suspending communication between the first and second volumes while maintaining operations for other volumes of the storage devices; causing the first volume to change from a source volume to a destination volume without destroying the first volume; causing the second volume to change from a destination volume to a source volume without destroying the second volume; after causing the first volume to change from a source volume to a destination volume and causing the second volume to change from a destination volume to a source volume, initiating a background copy of data from the source volume to the destination volume; and resuming data access operations to the first and second volumes independent of completion of the background copy, wherein, in response to a data access operation to the second volume and valid data for the data access operation existing only on the first volume, the data access operation to the second volume is satisfied by accessing data from the first volume and wherein, in response to a write of particular data to the second volume, the particular data is transferred from the second volume to the first volume irrespective of whether the background copy is complete.