How long should backups be retained?
If you create full backups on a daily basis as mentioned above, it is recommended that you keep at least 2 weeks worth of backups (14 last backups for each domain controller) in order to have sufficient history in case a problem goes undetected for a period of time.
To configure the retention policy for backing up Computer Collections, complete the Backup tab of the Computer Collection Properties dialog box. For more information, refer to Recovery Manager for Active Directory User Guide.
It is a good strategy to take one backup a week from at least one domain controller and archive it in case it is necessary to retrieve deleted information from a period past the online backup history that is available. These archived backups should be available for the complete tombstone lifetime period (e.g. 60 days or 180 days by default, depending on the Service Pack level).
For security reasons, keep at least one copy off-site in a properly-controlled environment in order to protect it from possible attacks by malicious individuals via the network.
For more information, refer to the Recovery Manager for Active Directory Deployment Guide.
