Patent ID: 7971025

Claim:
A method of allocating physical storage space to a volume in a storage system comprising: receiving an input/output (I/O) request to store the write data to the volume from a host; in response to said I/O request, determining whether the volume is designated for storing a first data type that is accessed frequently by I/O operations or designated for storing a second data type that is accessed less frequently than the first data type; and allocating the physical storage space for storing the write data, said physical storage space being allocated from a first logical partition designated for storing the first data type when said volume is designated for said first data type and from a second logical partition designated for storing the second data type when said volume is designated for storing said second data type after said determining, wherein said physical storage space is allocated from one or more array groups, each array group being comprised of a plurality of disk devices and each array group having the same total group capacity, wherein said each array group is partitioned into one of said first logical partitions and one of said second logical partitions, such that a ratio of a first storage capacity of said first partition to the total group capacity is established according to a predetermined quantity, wherein the physical storage space is not allocated to a portion of the volume until the portion of the volume is first targeted for storing write data, and wherein the physical storage space is allocated from said one or more array groups based on utilization of said one or more array groups.