Patent ID: 8028192

Claim:
A method comprising: replicating data from a primary computer to a secondary computer; generating a map based on at least one write request to a secondary data storage of the secondary computer, wherein the at least one write request is received after failover from the primary computer to the secondary computer, and the map records a write address for data written to the secondary data storage after the failover; receiving a read request from an application, wherein the read request is received during a failback from the secondary computer to the primary computer; synchronizing a primary data storage of the primary computer with the secondary data storage of the secondary computer, wherein the synchronizing is performed during the failback; updating the map, wherein the updating is performed during the failback; determining the location of a latest version of data corresponding to the read request by accessing the map during the failback, wherein the location may be within either the primary data storage or the secondary data storage; and reading the latest version of data during the failback from the location while the synchronizing is being performed.