EMC Symmetrix Remote Data Facility software provides remote storage replication for disaster recovery and ensures data and systems availability through remote site failover. EMC Symmetrix Remote Data Facility devices are configured in pairs. The mirroring relationship between the pairs becomes operational as soon as the EMC Symmetrix Remote Data Facility links are online. The EMC Symmetrix Remote Data Facility global memory stores information about the pair state of operating EMC Symmetrix Remote Data Facility devices. For information about EMC Symmetrix Remote Data Facility software, see the product documentation.