Veeam Backup & Replication utilizes VMware ESX snapshot capabilities to create and manage replica restore points. During the first replication job session, Veeam Backup & Replication creates a copy of the source VM on the target host. During every subsequent replication job session, it adds a new snapshot to the snapshot chain for the VM replica. Blocks of data that have changed since the last job run are written to the snapshot delta file, and the snapshot delta file acts as a restore point.
VM replica restore points are stored in a native VMware vSphere format next to replica virtual disk files, which allows Veeam Backup & Replication to accelerate failover operations. To fail over to the necessary point of the VM replica,Veeam Backup & Replication does not need to apply rollback files. Instead, it uses a native VMware vSphere mechanism of reverting to a snapshot.
You can specify retention policy settings for replication jobs — define how many retention points you want to keep for every VM replica. Veeam Backup & Replication will keep only the specified number of points and remove outdated snapshots.