A method for maintaining coherency between mirrored storage devices

摘要

Disclosed herein is a method for controlling a storage device controller connected to a storage device provided with a plurality of storage volumes for storing data respectively and an information processing apparatus for requesting an input/output of data so as to receive an input/output request from the information processing apparatus and execute an input/output processing of the data for each of the plurality of storage volumes. The method brings one (primary) of the plurality of storage volumes into correspondence with another (secondary) in which a copy of data is to be written when the data is written in the primary volume so as to form a pair group consisting of a plurality of pairs, each having such a primary volume and such a secondary volume. Upon receiving an input/output request from the information processing apparatus, the method starts resetting of the correspondence between storage volumes of each pair included in the pair group to decide whether or not it is after resetting of the correspondence is started that the request has been issued and executes an input/output processing after resetting the correspondence if the request is issued after resetting of the correspondence is started.