Patent ID: 7814272

Claim:
A method of storing data in a number of storage devices, the storage devices being under control of a storage manager external to the storage devices, the method comprising: under control of the storage manager, storing fixed-size blocks of data in a first set of storage devices including at least a first storage device; under control of the storage manager, causing a selected portion of the blocks to be stored, in a fault tolerant manner using block-based mirroring, in only the first storage device when the selected portion cannot be stored in a fault tolerant manner across a plurality of the storage devices; and in response to a change of composition of the first set of storage devices resulting in a second set of storage devices, the second set including at least the first storage device and a new storage device, causing, under control of the storage manager, automatic reconfiguring of storage of the selected portion of the blocks, using information from the first storage device, such reconfiguring including using the new storage device as part of a storage pattern providing fault tolerance for the selected portion across a plurality of the storage devices in the second set, so that at least some storage space, on the first storage device, that had been utilized to provide fault tolerance for the selected portion becomes available for storage of other blocks of data.