Patent ID: 7685129

Claim:
A method of determining when to migrate a data set, comprising: providing performance criteria for the data set; measuring performance of the data set at a current location to provide a measured performance of the data set; if the measured performance indicates that the data set is not performing according to the performance criteria at the current location, choosing a new location for migrating the data set and migrating the data set to the new location, wherein migrating the data set includes moving the data set to the new location irrespective of whether other applications are accessing the data set and using a migration process that is substantially transparent to the other applications, wherein the data set is migrated in portions to the new location, and wherein, during migration of the data set, I/O requests from the other applications for access to a portion of the data set that has been migrated to the new location are diverted to the migrated data set portion at the new location and I/O requests from the other applications for access to a portion of the data set that has not yet been migrated are performed on the data set portion at the current location; and if the measured performance indicates that the data set is performing according to the performance criteria at the current location, determining that migration of the data set is not indicated based on the measured performance and the performance criteria.