STORAGE SYSTEM AND DATA COPYING METHOD IN THE STORAGE SYSTEM

摘要

Even if an error occurs in one of a main storage system and a first sub storage system during a maintenance of the other storage system, data which has been received from an upper-node device is not lost and the storage system can resume a process subsequent to the data. When both of the main storage system and the first sub storage system enter a suspend state, the upper-node device transfers from the first sub storage system to the second sub storage system, differential data between copied data which have been stored in a first sub volume and a second sub volume.