It is vital to achieve a disaster recovery system that allows a backup site to take over a primary site?s IT services while the primary site is down. We propose a flexible replication mechanism based on service requirements such as system performance, recovery time objective (RTO), and recovery point objective (RPO). For high flexibility, the mechanism controls the replication schedule by monitoring the application?s database accesses in the database connection library and matching the accesses with previously registered access patterns. In our experiments, we confirmed that the proposed mechanism outperforms other existing mechanisms, especially in situations with network delays and packet losses.