For the Failback to the specified location, Veeam Backup & Replication must transfer the entire VM data, including its configuration and virtual disc content. Choose this option if you cannot use the original VM or restore it from a backup.
Because Veeam Backup & Replication only needs to transfer differences between the original/recovered VM and VM replica, the failback to the original virtual machine restored in a different location option helps reduce recovery time and network traffic.
Failback is returning operations to the primary site after a disaster recovery event. It reverses the failover process by replicating any changes made to the virtual machine during the Failover state back to the primary site and then redirecting users and applications back to the primary site.