Considerations and Limitations

Replication has the following requirements and limitations:

Due to VMware vSphere limitations, if you change the size of VM disks on the source VM, Veeam Backup & Replication deletes all available restore points (represented as VM snapshots) on the VM replica during the next replication job session. For more information, see this VMware KB article.
Due to a change in ESXi 6.0 Update 1, replication and Quick Migration to vVol datastores are not possible with either Veeam or native VMware vSphere replication.
The target host must support the hardware version of the VM that you plan to replicate. For the compatibility table, see this VMware KB article.
If you assign the role of a backup proxy to a VM, you should not add this VM to the list of processed VMs in a job that uses this backup proxy. Such configuration may result in degraded job performance. Veeam Backup & Replication will assign this backup proxy to process other VMs in the job first, and processing of this VM itself will be put on hold. Veeam Backup & Replication will report the following message in the job statistics: VM is a backup proxy, waiting for it to stop processing tasks. The job will start processing this VM only after the backup proxy deployed on the VM finishes its tasks.
Replication of VM templates is not supported.
If you use tags to categorize virtual infrastructure objects, check limitations for VM tags. For more information, see VM Tags.
How Veeam Backup & Replication requests to assign MAC addresses to replicas depends on the MAC allocation mode configured on the vCenter Server:

Automatic allocation. If replica is located on the same ESXi host or vCenter Server, new MAC address is assigned. If replica is located on another ESXi host or vCenter Server, MAC address is preserved.
Manual allocation. MAC address is preserved.
Due to Microsoft limitations, you cannot use Microsoft Entra ID (formerly Azure Active Directory) credentials to perform application-aware processing on VMs running Microsoft Windows 10 (or later).
If a job is unable to complete within 21 days period, it will be stopped with the Failed status.