Patent ID: 8639969

Claim:
A storage system comprising: a plurality of drives, wherein each of the plurality of drives is configured to include a plurality of parcels; and a controller configured to: provide a virtual volume to a host computer; and store data into the plurality of drives by stripes, wherein each stripe includes M data and N parity data where the M and N are integers, the N parity data is calculated based on the M data for each stripe, the M data and N parity data are stored in M+N parcels of the plurality of parcels respectively, and each of the M+N parcels belongs to different M+N drives respectively, wherein the plurality of parcels include first M+N parcels including a first stripe and second M+N parcels including a second stripe, wherein a first drive of the plurality of drives includes both one of the first M+N parcels and one of the second M+N parcels, and a second drive of the plurality of drives includes either one of the first M+N parcels or one of the second M+N parcels, and wherein a plurality of pages are created on the M+N parcels, where each of the pages includes a plurality of stripes and each of the pages is allocated to the virtual volume in page unit according to a write command.