The FastResync feature (previously called Fast Mirror Resynchronization or FMR) performs quick and efficient resynchronization of stale mirrors (a mirror that is not synchronized). This feature ncreases the efficiency of the VxVM snapshot mechanism, and improves the performance of operations such as backup and decision support applications. Typically, these operations require that the volume is quiescent, and that they are not impeded by updates to the volume by other activities on the system. To achieve these goals, the snapshot mechanism in VxVM creates an exact copy of a primary volume at an instant in time. After a snapshot is taken, it can be accessed independently of the volume from which it was taken.
In a Cluster Volume Manager (CVM) environment with shared access to storage, it is possible to eliminate the resource contention and performance overhead of using a snapshot simply by accessing it from a different node.