To use vSphere HA, you must be aware of the following additional interoperability issues.
VM Component Protection
VM Component Protection (VMCP) has the following interoperability issues and limitations:
VMCP does not support vSphere Fault Tolerance. If VMCP is enabled for a cluster using Fault Tolerance, the affected FT virtual machines will automatically receive overrides that disable VMCP.
VMCP does not detect or respond to accessibility issues for files located on vSAN datastores. If a virtual machine's configuration and VMDK files are located only on vSAN datastores, they are not protected by VMCP.
VMCP does not detect or respond to accessibility issues for files located on Virtual Volume datastores. If a virtual machine's configuration and VMDK files are located only on Virtual Volume datastores, they are not protected by VMCP.
VMCP does not protect against inaccessible Raw Device Mapping (RDM)s.
vSphere HA can be used with IPv6 network configurations, which are fully supported if the following considerations are observed:
The cluster contains only ESXi 6.0 or later hosts.
The management network for all hosts in the cluster must be configured with the same IP version, either IPv6 or IPv4. vSphere HA clusters cannot contain both types of networking configuration.
The network isolation addresses used by vSphere HA must match the IP version used by the cluster for its management network.
IPv6 cannot be used in vSphere HA clusters that also utilize vSAN.
In addition to the previous restrictions, the following types of IPv6 address types are not supported for use with the vSphere HA isolation address or management network: link-local, ORCHID, and link-local with zone indices. Also, the loopback address type cannot be used for the management network.
To upgrade an existing IPv4 deployment to IPv6, you must first disable vSphere HA.