In an Exchange 2010 Database Availability Groups (DAG) environment, NetBackup tracks the success or failure of a backup attempt for each passive copy database backup. This information is stored in the Backup Status database on the NetBackup master server. This status is used in subsequent backup attempts for each database in a DAG to help determine which Exchange node to perform a passive copy database backup from.

If the last backup was successful, NetBackup performs the subsequent passive copy database backup attempt on the same Exchange server, if possible. If the last backup attempt failed, NetBackup attempts to find a different Exchange server to perform the subsequent passive copy database backup attempt on.