Patent ID: 7984327

Claim:
A data processing method, comprising: receiving data objects from a data source for storage by a primary storage device; caching a respective first instance of each of at least some of the received data objects in a disaster-proof storage unit that is collocated with the primary storage device, and sending a respective second instance of each received data object for storage in a secondary storage device that is remote from the primary storage device; sending from the disaster-proof storage unit to the remote secondary storage device a list of respective identifiers of the data objects that are cached in the disaster-proof storage unit at a given point in time; following an event that renders at least some of the data objects on the primary storage device inaccessible at the given point in time, receiving a request sent to the secondary storage device to access a given data object; and choosing, at the secondary storage device, responsively to the list, to serve either the cached first instance or the stored second instance of the given data object in response to the request.