This is an archive version of the document. To get the most up-to-date information, see the current version.

Requirements and Limitations

CDP has a set of requirements and limitations.

Requirements

The following requirements apply to CDP:

CDP is included in the Veeam Universal License. When using a legacy socket-based license, the Enterprise Plus edition is required.
VMware vSphere edition must be VMware vSphere Standard Edition or higher. VMware vSphere Essentials Kits editions are not supported.

For supported platforms, see Platform Support.
For supported source and target datastores, see Veeam CDP Source and Target.
Cisco HyperFlex 4.5 (2a) and later can be used as a source or target only with VMware vSphere 7.0 U2 and later. With the previous versions of VMware vSphere, Cisco HyperFlex is not supported.
All hosts in a cluster must be of the same major version: 7.x or 6.x (6.5, or 6.7, or a combination of 6.5 and 6.7 is supported). In turn, all clusters managed by the same vCenter Server must also be of the same major version.
You can replicate data between vCenter Servers of different versions. However, if you replicate data within one vCenter Server, and this vCenter Server includes hosts of different versions (6.5 and 6.7), your CDP policy may fail. In this case, go to the vSphere Client and delete the Veeam CDP Replication vm storage policies as described in VMware Docs. Then, in the Veeam Backup & Replication console, relaunch the CDP policy.
The target cluster must support hardware versions of VMs on the source cluster (VMs that you plan to protect).
You must configure CDP for one cluster on one backup server only. If you add a cluster to another backup server and install I/O filter (filter required for CDP) on it, CDP policies on the first backup server will fail. For more information on I/O filter, see I/O Filter.
The backup server must have at least 16 GB RAM.
VMs that you plan to protect must not have snapshots at the moment when the CDP policy starts for the first time. Further, you can add these VMs to backup jobs that will create snapshots. However, you must not create snapshots by other means, for example, manually or by another software. This may disrupt further replication operations or cause loss of data.
During the initial synchronization, Veeam Backup & Replication needs double space allocation for VMs with thick-provisioned disks on the target host. After the initial synchronization finishes, Veeam Backup & Replication frees half of the allocated space for such VMs. This is a part of mechanism required to support protection of disks newly added to the original VMs.
Network between infrastructure components required for CDP must be minimum 1 Gbps. We recommend to use 10 Gbps or faster and MTU 9000.
If you enable VM encryption on VMware side, make sure that the Allow I/O filters before encryption parameter is set to True in the Default encryption properties storage policy component.
For VMware CDP proxy requirements, see VMware CDP Proxy.

Limitations

When planning to use CDP, mind the following limitations:

CDP works only for powered on VMs. However, for VMs with IDE hard drives you must power off VMs before the initial synchronization. This is required to apply a new storage policy to VMs. For more information, see How CDP Works.
One VM can be processed only by one CDP policy.
CDP is not supported for VMs to which VM storage policies with multiple datastore specific rule sets apply. If you need to define datastores to be used for placement of the VMs, you can add a tag rule for vSAN instead of a tag based placement datastore specific rule. For more information on how to create tag rules for vSAN, see VMware Docs.
VM replicas can be powered on only using the failover operation; manual power on is disabled.
Testing CDP replicas with Virtual Labs is currently not supported.
On the target host, Veeam Backup & Replication does not allow you to migrate VM replicas using VMware vSphere Storage vMotion. Note that host vMotion is supported.
Shared disks, physical RDM and SCSI bus sharing are not supported. Note that vRDM disks are supported.
The maximum number of CDP policies that can be created on one backup server is 100.
The maximum supported number of disks for one VM is 50. The maximum number of disks for one ESXi host is 500.
The maximum number of long-term restore points for one disk is 95.
Data encryption rules do not apply to traffic between the ESXi host and VMware CDP proxy. For more information on the rules, see Enabling Data Encryption.