Patent ID: 6938120

Claim:
A method to form one or more premigration aggregates comprising a plurality of least recently accessed virtual volumes, comprising the steps of: maintaining (N) virtual volumes in an information storage medium; determining the number (R) of said plurality of virtual volumes to remove from said information storage medium wherein R is greater than 1; selecting the (R) least recently accessed virtual volumes; forming one or more premigration aggregates; assigning each of said (R) selected virtual volumes to one of said one or more premigration aggregates; establishing a minimum total aggregate transfer size; determining if any of said one more or premigration aggregates are larger than said minimum total aggregate transfer size; operative for each of said premigration aggregates that are larger than said minimum total aggregate transfer size: writing that premigration aggregate to one or more physical volumes; and removing that premigration aggregate from said information storage medium.