Patent ID: 7308601

Claim:
A disk array control program operable to drive a computer of a disk array control apparatus for processing I/O requests from an upper apparatus, directed to a disk array system provided with a plurality of disk apparatuses each having a redundant configuration to execute: a first recovery processing step of, when notified of an error detected by patrol processing of the disk apparatuses, reading out data corresponding to a location of the error from a normal disk apparatus and writing the data into an error disk apparatus to thereby eliminate the error; and a second recovery processing step of, if it is determined that the content of the error notification is abnormality of an identifier indicating the order of writing data, retrieving a correct write address indicated by the identifier, comparing data of the error disk apparatus with data of the normal disk apparatus, determining that a lost write exists in case of mismatch, and writing data read out from the normal disk apparatus into the error disk apparatus to thereby eliminate the lost write.