A method and a controller for managing a storage array is presented. The storage array is divided into a first subset of storage devices and a second subset of storage devices according to degrees of wear of storage devices, such that a degree of wear of each of storage device in the first subset is greater than or equal to a degree of wear of any storage device in the second subset, and then, to-be-written data are written into the physical storage devices in the first subset. Therefore, service lives of storage devices in the second subset may be extended relatively by shortening service lives of storage devices in the first subset.