In a Continuous Data Protection (CDP) deployment, there is always one (and only one) master Agent on which files can change. This master Agent is typically connected at all times to the Vault that keeps the data continuously backed up, but you should prepare for an unanticipated disconnection, in case your backup computer should go down or lose connection for some reason.
You can configure the software to detect automatically when a master is disconnected unexpectedly, and take steps to redirect end users to a new file server. This new file server is updated automatically with the original master's most recent data, and will act as a temporary master.
A CDP deployment can have as many slave Agents as needed, each with its own local copy of the Job’s files. Additionally, each is able to become a master Agent at any time. This process occurs automatically; the switch does not need any manual intervention.