Microsoft Exchange hosted Virtual enviroment, it’s recommended to create a single job and add all the DAG node in the same node for the better deduplication and compression.
Also, to avoid performances impact it’s recommended to have passive only Exchange node for backup.
To avoid failover during the backup you should adjust cluster timeouts:
Adjust Microsoft settings for failover sensitivity (in bold, run from command line): cluster /prop SameSubnetDelay=2000:DWORD (Default: 1000) cluster /prop CrossSubnetDelay=4000:DWORD (Default: 1000) cluster /prop CrossSubnetThreshold=10:DWORD (Default: 5) cluster /prop SameSubnetThreshold=10:DWORD (Default: 5)
Use Network (NBD) mode setting on Source Backup Proxy as opposed to Appliance (hotadd) mode for your backup and/or replication jobs in Veeam
Disable all background scanning and/or maintenance tasks occurring in Exchange, or any other tools that are being leveraged against the system at the time of backup such as Email Archiving, anti virus scanning etc.