To minimize the impact to network delivery and receipt of messages and to keep a large volume of traffic off of a LAN (Local Area Network), back up your Exchange database locally by using a LAN-free data path. A LAN-free, or preferred, data path uses a MediaAgent that is installed on the same client as the Exchange database. LAN-free data paths are used automatically when they are available. If a LAN-free data path is not available, you can use a LAN-based backup. We recommend that you use dedicated networks for LAN-based backups.
DAG environments can be distributed geographically and connected by a WAN (Wide Area Network).
Depending on which database is backed up, the backup might run across the WAN, which would increase congestion on the network. We recommend that you prevent backing up Exchange databases over a WAN by installing MediaAgents at each geographical location. Create LAN-free storage policies so that databases are backed up locally. Alternatively, if LAN-free data paths are not available at each location, create LAN-based storage policies.
For information about data paths, see GridStor® (Alternate Data Paths).
When multiple data paths are available, such as in a DAG environment, the sequence or alternate use of data paths can be overridden at the subclient level.