Computer system remote copying system and computer system

摘要

When a virtual tape of the main storage system is updated, journal data is created. The journal data is transmitted to the disaster recovery storage system asynchronously with the timing at which the write data is received. The journal data includes a marker to notify of the start of updating and a marker to notify of the completion of updating. The disaster recovery storage system prohibits the use of the copy destination data during the period from start of updating until completion of updating, and permits referencing the copy destination data during other periods.