Patent ID: 7941697

Claim:
A computer system comprising: a client; and a storage subsystem coupled to the client; wherein the computer system is configured to: detect a failure of a storage region including at least a portion of a storage device; configure an overlay storage device to temporarily overlay the failed region, in response to detecting said failure; maintain an association between the overlay storage device and the failed region; and maintain a record of changes made to the overlay storage device while the region is in a failed state; wherein the storage subsystem comprises a plurality of storage locations addressable as rows and columns in an array, each column of the array being stored in a separate storage device of a plurality of storage devices configured to store data, and wherein for a given row in the array, a storage device of the plurality of storage devices that is storing data corresponding to the given row is selected to act as a coordinating storage device configured to coordinate reads and writes of data for the given row.