Patent ID: 7640452

Claim:
A method for reconstructing data in case of the failure of two HDs (Hard Disks) of a RAID (Redundant Array of Independent Disks), wherein the RAID includes at least three HDs and a RAID controller, file data is divided into strips stored on different data blocks of the different HDs respectively, comprising the steps of: reading super blocks of all the HDs for obtaining number of the HDs and time of a previous operation of the RAID stored on the super blocks of all the HDs; comparing the number of the HDs and the time of the previous operation of the RAID obtained from all the HDs with each other; reading common data used in a previous degraded mode of the RAID; writing the common data used in the previous degraded mode into the super blocks of all the HDs; recovering a configuration of the RAID into a degraded mode again; reading data from the data blocks of defective HDs; detecting whether any of the data blocks is defective; reading intact data from the data blocks of the defective HDs and duplicating the intact data into an external storage device connected to the RAID; and recording location of the defective data block into the external storage device.