Patent ID: 6757839
Filing Date: 2004-06-29
Classification: G06F

Abstract:
A storage system comprising:a plurality of disk units storing data of a record group, said record group including a plurality of data records and a parity record that has redundant data for recovering data of said plurality of data records, wherein data of each of said parity record and said plurality of data records is stored in a different one of said plurality of disk units; a cache memory; and a control unit, wherein said control unit receives a write request and write data to be written into one of said plurality of disk units from a processing unit coupled to said storage system, stores said write data into said cache memory, and reports the completion of said write request to said processing unit, and after reporting the completion of said write request, said control unit checks whether or not data of records necessary for generating updated value of said parity record is stored in said cache memory, loads data of one or plurality of records necessary for generating the updated value of said parity record when the data of said one or plurality of records is not stored in said cache memory, generates the updated value of said parity record, writes the updated value of said parity record to one of said plurality of disk units which stores data of said parity record, and writes said write data to one of said plurality disk units.