Patent ID: 8171100

Claim:
A system for caching data in a plurality of storage systems, each storage system accessing a same shared data set comprising a set of storage objects, each storage object having an associated set of attributes that describe the storage object, the system comprising: an owner storage system configured for: storing the shared data set; and generating and transmitting a first image of the shared data set to a remote storage system over a network; and the remote storage system configured for: receiving and storing the first image of the shared data set; receiving a read request for a first data of a first storage object in the shared data set; sending an attribute request to the owner storage system for only owner attributes of the first storage object; receiving only the owner attributes of the first storage object and no data of the first storage object from the owner storage system; retrieving remote attributes of the first storage object from the first image; upon determining that the owner and remote attributes of the first storage object match: retrieving the first data of the first storage object from the first image; storing first information indicating that the owner and remote attributes of the first storage object match; receiving a read request for a second data of the first storage object; using the first information to determine that the owner and remote attributes of the first storage object match; and retrieving the second data of the first storage object from the first image, wherein the set of attributes that describe a storage object comprise information indicating when the storage object was last modified.