Each Mirror Replication Agent instance uses an embedded database (the Mirror Replication Agent System Database, or RASD) to manage its system data repository, which stores information about the primary database schema, mirror log devices, and transaction log metadata.
The system data repository allows Mirror Replication Agent to continue processing transactions from the mirror log devices if the primary database goes offline. The RASD provides database recovery features (such as backup and restore, and software-mirrored devices) to support Mirror Activator system recovery and fault tolerance.
When you create a Mirror Replication Agent instance, the RASD is created automatically. The system data repository is populated with the information that the Mirror Replication Agent needs when you initialize the Mirror Replication Agent instance.
