Patent ID: 7386664

Claim:
A method comprising: receiving a read operation on a region of a data volume at a first module of a first storage virtualization device, wherein said data volume comprises at least a first mirror storage element and a second mirror storage element, and determining a state indicated by synchronization data corresponding to said region of said data volume in response to receiving said read operation, wherein said synchronization data is stored in a first synchronization map; processing said read operation using said first module if said synchronization data is determined to indicate a first state; processing said read operation using a second module of said first storage virtualization device if said synchronization data is determined to indicate a second state, wherein said second module comprises a second processing device configured to process input/output operations including said read operation and to maintain said first synchronization map; receiving a second synchronization map from a second virtualization device at said first virtualization device; and copying said second synchronization man to said first synchronization map using said second processing device, following a failure of said second virtualization device.