A redundant array of independent disks (RAID) storage device including; a memory device including first memory devices configured to store at least one of data chunks and corresponding parity (data chunks/parity) and a second memory device configured to serve as a spare memory region, and a RAID controller including a RAID internal memory configured to store a count table and configured to control performing of a rebuild operation in response to a command received from a host, wherein upon identification of a failed first memory device, the RAID controller accesses used regions of non-failed first memory devices based on the count table and rebuilds data of the failed first memory device using the second memory device.

A redundant array of independent disks (RAID) storage device including; a memory device including first memory devices configured to store at least one of data chunks and corresponding parity (data chunks/parity) and a second memory device configured to serve as a spare memory region, and a RAID controller including a RAID internal memory configured to store a count table and configured to control performing of a rebuild operation in response to a command received from a host, wherein upon identification of a failed first memory device, the RAID controller accesses used regions of non-failed first memory devices based on the count table and rebuilds data of the failed first memory device using the second memory device.

A technique for data reconstruction includes determining a plurality of types of data stored in a storage disk; determining an order in which data reconstruction is to be performed on the plurality of types of data based on corresponding likelihoods that the plurality of types of data are expected to be accessed; and performing the data reconstruction on the plurality of types of data in the determined order. Such a technique can improve system performance during data reconstruction and reduce the access delay.

A technique for data reconstruction includes determining a plurality of types of data stored in a storage disk; determining an order in which data reconstruction is to be performed on the plurality of types of data based on corresponding likelihoods that the plurality of types of data are expected to be accessed; and performing the data reconstruction on the plurality of types of data in the determined order. Such a technique can improve system performance during data reconstruction and reduce the access delay.