In a DAG environment, to specify the backup source, you can manually select a single server, or you can have the software automatically select the server (the default value).
To avoid backup operations from slowing down other processes that are running on the active server, you can specify that the software select a passive server by selecting the Backup from passive copy check box.
To ensure that backup operations run on the server that is least likely to become active in a failover case, you can select the Use last activation preference to select passive copy check box.
Regardless of which backup source you use, you can back up Mailbox databases and Public Folder databases.
From the navigation pane, go to Protect > Applications > Exchange.
The Exchange page appears.
Click an Exchange database.
The Exchange Database page appears.
In the Subclients section, click the subclient for which you want to configure the backup source.
The subclient page appears.
In the Server details section, click Edit.
The Server details dialog box appears.
Specify whether to select the backup source manually or automatically:
To manually select the backup source, select Manual selection, and then, for each database, select the server that you want to use as the backup source.
To have the software automatically select the backup source, complete the following steps:
Select Automatic selection.
To use a passive server, select the Backup from passive copy check box.
To use the active server when no passive server is available, select the Backup from active copy if no passive copy is available check box.
To run backup operations on the server that is least likely to become active in a failover case, select the Use last activation preference to select passive copy check box.