Abstract: The present invention provides a system and method for handling large transactions by a storage virtualization system. Current storage virtualization systems can only manage a limited number of data objects stored on an associated NAS system because of the cost or hardware constraints of physical main memory. The present invention will enable a storage virtualization system to increase the number of data objects managed by a factor of five or more by using an associated secondary memory store, such as a disk, to store information or metadata about data objects stored on associated NAS systems. The invention also provides a method for moving metadata from the storage virtualization system memory to the secondary store and back, and recovering metadata if corrupted. The invention thereby increases the number of data objects handled by the storage virtualization system with negligible loss of performance as perceived by clients of the storage virtualization system.