Parity rotation in storage-device array

In one embodiment, a method for writing data to a storage-device array (i) including three or more storage devices and (ii) having a plurality of stripes, each stripe having two or more sector levels, each sector level containing one sector on each storage device in the array at corresponding addresses across the storage devices. The method includes: (a) calculating a parity index based on (i) an index value for a current stripe and (ii) the number of storage devices in the array, the parity index identifying a first storage device for parity data for the current stripe; and (b) at each sector level of the current stripe: (b1) writing parity data to the first storage device identified by the parity index; and (b2) writing information to the remaining storage devices.