a method for displaying a state of a copy pair which is a pair of logical volumes belonging to one or a plurality of storage sub systems connected to a task server , including : monitoring periodically , by a backup management program on the task sever , an operation condition of an application on the task server ; notifying , by the backup management program , a maintenance to a control program on the storage sub system , if the application is on a stop condition at some time ; setting , by the control program which receives the notification , “ on - maintenance ” to an action mode on the storage sub system ; after a maintenance by a user and at time of a restart of the application , checking , by the backup management program , the operation condition of the application and notifying a release of the maintenance to the control program ; and setting , by the control program which receives the notification of the release , the action mode of the storage sub system to a normal condition .