A disaster recovery system and a method therefor, having: a function for receiving write requests from a host computer to write log information indicating the contents of a database process executed for a database buffer on a main site, database data updated on the database buffer and status information indicating the position of log information used for disaster recovery; a function for transferring the received write request for log information to a recovery site by a synchronous remote copy process; and a function for transferring the received write request for database data to the recovery site by an asynchronous remote copy process. While remote copy can be executed at a long distance without data loss, the deterioration of the performance of a database process on a main site can be suppressed.