#VCP #Concept Feature of vSphere that provides VM Protection without any downtime for the applications running on the VM. The protected VM is called the primary VM, the replicated VM is the secondary VM. VM is replicated to a secondary VM on another host, if the host fails active VM will be switched to the secondary VM. Primary and secondary VM are monitoring the state of each other continuesly. Latency is increased on both VMs, as they need to be replicated through the network. ## Restrictions maximum amount of FT enabled per Host is 4 per default, can be changed via ESXi Host advanced setting `das.maxftvmsperhost` maximum vCPUs per host that have FT enabled is per default set to 8, can be changed in ESXi Host advanced setting `das.maxftvcpusperhost` Further the following features are not supported on FT enabled VMs: - Snapshots - Storage vMotion - linked clones - Storage based policy management - cannot reside on vVOL datastores - VBS is not compatible ### licensing The number of vCPUs supported by a single fault tolerant VM is limited by the levle of licensing - vSphere Standard & Enterprise - up to 2 vCPUs - vSphere Enterprise Plus - up to 8 vCPUs ## Requirements - Appropriate license - 10Gbit between ESXi hosts - dedicated 10Gbit network is recommended ## 🔗Resources