SRDF

SRDF, or Symmetrix Remote Data Facility, is EMC’s data replication technology for EMC Symmetrix storage systems. It enables disaster recovery and business continuity by maintaining remote copies of data on one or more mirror sites. SRDF operates over a storage network and supports different replication styles to suit distance, latency, and recovery objectives. At its core, SRDF uses RDF pairs, which link a local Symmetrix to a remote Symmetrix and mirror selected volumes. It can coordinate multiple volumes through consistency groups to preserve transactional integrity across related data sets.

SRDF supports several replication modes. SRDF/S is synchronous replication, where write acknowledgments are not completed until the remote site also confirms the write, providing very low or zero RPO but requiring low latency connections. SRDF/A is asynchronous replication, where local clients acknowledge writes before remote updates are finished, allowing greater distances and bandwidth tolerances at the cost of higher potential RPO. SRDF/C is cascaded replication, which enables replication from a primary site to a secondary site that then mirrors to a further remote site, enabling multi-site protection.

Management and deployment considerations. SRDF requires appropriate licensing on the involved Symmetrix arrays and is typically configured and monitored through EMC management tools such as Unisphere for Symmetrix or legacy interfaces. It uses dedicated replication links within the storage network, often with dual channels (for redundancy) and carefully planned network topology to meet stated RPO/RTO targets. SRDF is commonly integrated with broader data protection workflows, including backup and disaster recovery planning, and is designed to support rapid failover and failback in controlled DR events.