Patent ID: 7065611

Claim:
A data migration method in a virtualization system comprising: determining a plurality of LU (logical unit) classes, wherein each of at least some virtual LUs from among a plurality of virtual LUs is associated with one of said LU classes; gathering from said virtualization system activity information relating to IO activity in physical devices which constitute a virtual LU; and setting up for a migration operation of a first virtual LU comprising: determining a candidate LU class based on IO activity relating to said first virtual LU; presenting said candidate LU class to a user; presenting a list that identifies said plurality of LU classes; and receiving a selected LU class, said selected LU class being one of said candidate LU class and a user-specified LU class, wherein data contained in said first virtual LU can be migrated to a second virtual LU, said second virtual LU belonging to a target LU class.