Patent ID: 8595454

Claim:
A method comprising: detecting that a first set of one or more blocks of client data has not been relocated subsequent to a prior off-host backup operation, wherein the detecting is performed in response to a request to perform a new off-host backup operation, and the detecting is performed without using recalculated mapping information; detecting that a second set of one or more blocks of the client data has been relocated subsequent to the prior off-host backup operation; providing a media server with a previously calculated set of mapping information for the first set of one or more blocks, in response to the detecting that the first set of one or more blocks has not been relocated, wherein the previously calculated set of mapping information was calculated in response to a request to perform the prior off-host backup operation, and the previously calculated set of mapping information was provided to the media server in conjunction with the prior off-host backup operation; recalculating mapping information for the second set of one or more blocks, in response to the detecting that the second set of one or more blocks has been relocated; and providing the media server with the recalculated mapping information instead of previously calculated mapping information for the second set of one or more blocks, subsequent to the recalculating.