Patent ID: 8812806

Claim:
A machine implemented method for migrating a virtual storage system from a source storage system having access to a source storage device to a destination storage system having access to a destination storage device, where the source storage system executes a processor executable storage operating system for presenting the virtual storage system to a plurality of client systems and managing the source storage device to read and write information at the source storage device for the plurality of client systems via the virtual storage system, comprising: prior to entering a cut-over duration for completing a migration operation, determining a projected workload of the source storage system during the cut-over duration; wherein the plurality of client systems can access the source storage device via the virtual storage system during the migration operation, except during the cut-over duration when access to the source storage device is restricted; determining a projected work load of the destination storage system during the cut-over duration when access to the destination storage system is restricted; wherein the projected workload of the source storage system and the destination storage system during the cut-over duration is based on a factor that indicates how busy a processor of the source storage system and a processor of the destination storage system will be during the cut-over duration; a number of sequential and random read and write operations at the source storage system and the destination storage system during the cut-over duration; and a numerical factor to quantify an affect of the sequential and random read and write operations on the migration operation; determining projected utilization of the destination storage device after the cut-over duration, if the virtual storage system were to be successfully migrated from the source storage system to the destination storage system within the cut-over duration; estimating a likelihood of success for completing the migration operation in response to the migration request within the cut-over duration; and proceeding with the migration operation in response to the migration request based on the estimated likelihood of success when the migration operation can be completed within the cut-over duration and an acceptable projected utilization of the destination storage device after the migration is completed.