Patent ID: 8046537

Claim:
A method for managing storage of data in a network comprising a plurality of host data processors coupled to a virtualization engine, the virtualization engine being coupled to a plurality of physical storage media, each physical storage medium being assigned a tier level, the method comprising: storing a threshold storage access value associated with each tier level; presenting at least one virtual disk to a host data processor; receiving I/O requests to the virtual disk from the host data processor; storing metadata for blocks of the physical storage, the metadata identifying: mappings of the physical block to one or more corresponding block(s) of a virtual disk; and an access value for each physical block representing the rate of access to the block by host data processors; and the tier level of the block; and periodically comparing the access value of a physical block to the threshold access value associated with its tier level, marking the block for migration to another tier level in dependence on the result of the comparison; and further comprising storing a break count value in the metadata for a physical block in dependence of the result of the comparison.