Considerations and Limitations
If you plan to use CDP to protect your workloads, consider the following requirements and limitations.
Licensing
The availability of the feature depends on the license you use. For more details about licensing support, see Veeam Data Platform Feature Comparison.
Platforms and Datastores
- CDP is supported for a limited number of platforms and versions. For more information on platforms and requirements for them, see Workloads.
- CDP supports specific source and target datastores. For more information, see Veeam CDP Source and Target.
Infrastructure Components
- The backup server must have at least 16 GB RAM.
- CDP proxy must meet the requirements listed in section CDP Proxy.
- The network between the infrastructure components must suit the load on your infrastructure. We recommend that you use at least 100 Mbps network. Slower networks cannot handle the generated disk traffic without interruption. The better performance is proven on 10 Gbps networks or faster and MTU 9000.
- You must configure CDP for one cluster on one backup server only. If you add a cluster to another backup server and install the I/O filter (filter required for CDP) on it, CDP policies on the first backup server will fail. For more information on the I/O filter, see I/O Filter.
When you upgrade Veeam Backup & Replication to the current version, you can postpone the I/O filter upgrade on vCenter Servers. Veeam Backup & Replication supports postponing the I/O filter upgrade for 13.x minor releases and for upgrades from the filter version 12.3.1.x or 12.3.2.x to 13.x. It is recommended that all clusters in one vCenter Server use the same I/O filter version. Partially upgraded vCenter Servers have limited functionality. You cannot add VMs from non-upgraded hosts to CDP policies, commit failback and perform some other operations. You should keep the I/O filter at the latest version to reduce the risk of potential issues.
- The maximum number of CDP policies that can be created on one backup server is 400.
- If you upgrade the primary version of hosts in the vCenter Server (for example, from ESXi version 7 to 8), you must upgrade the I/O filter version on this server. Perform this upgrade either alongside the ESXi upgrade or immediately after it. For more information, see Updating and Uninstalling I/O Filter.
- If you add a new cluster or host to a vCenter Server after the I/O filter is installed on the existing clusters and hosts, you must launch the I/O Filter Management wizard. Make sure that check boxes are selected near all clusters where the I/O filter must be present and finish the wizard. After you finish the wizard, Veeam Backup & Replication requests the vCenter Server to install the I/O filter (if required), and to configure it.
- Sizes of all VM disks must be set as integer values.
Veeam Backup & Replication does not support protection of workloads with 4K native disks (disks with 4096 bytes logical sector size).
- VMs that you plan to protect must not have snapshots at the moment the CDP policy starts for the first time. For example, if a VM is already added to a backup job, make sure that the scheduled backup session does not overlap with the CDP policy first run.
- The hardware versions of VMs that you plan to protect must be supported on the target cluster.
- 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.
- 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.
- Shared disks, physical RDM and SCSI bus sharing are not supported. Note that vRDM disks are supported.
- One VM can be processed only by one CDP policy.
- 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 source VMs.
- The maximum number of disks attached to one VM is 50.
- If you change the VM disk size after the replication process starts, Veeam Backup & Replication starts the replication process anew. This action removes restore points created before the size change and starts the initial synchronization.
- The maximum number of long-term restore points per disk is 95.
- For VMs encrypted on VMware side, consider the following:
- Make sure that the Allow I/O filters before encryption parameter is set to True for the VM storage policy component. For more details, see VMware vSphere documentation.
- To create encrypted CDP policy, select the encrypted datastore at the Destination step of the wizard. For more information, see Creating CDP Policies.
- Encryption for transaction log files that contain incremental changes for disks is not supported. For more information, see CDP Replication Chain.
Replicas
- On the target host, Veeam Backup & Replication does not allow you to migrate replicas using VMware vSphere Storage vMotion. Note that host vMotion is allowed. However, note that during failover, host vMotion is not allowed.
- Replicas can be powered on only using the failover operation; powering on replicas manually is not supported.
- Veeam Backup & Replication supports testing. For more information, see SureReplica.
- SureReplica verification does not prevent CDP policy from running.
Related Topics