DISK ARRAY DEVICE AND ITS CONTROLLING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce overhead at the time of writing data in a disk array system of RAID (level 5) for dispersing data and improving throughput. SOLUTION: A duplex area is formed in a group for preparing parity. At the time of writing, data to be written are temporarily written in the duplex area (step 502) and writing processing in a CPU is ended at the time (step 508). Parity preparation is performed at succeeding proper timing (516) and the parity is written in an SCSI drive (522). Namely parity preparation is efficiently scheduled differently from data writing. Since the data to be written are written in the duplex area at the time of data writing and the writing of data in the SCSI drive and parity preparation are timewise independently processed, the overhead of parity preparation at the time of writing is hidden from the CPU.