Configure resource group vSphere hosts per vSphere design guidelines. Enable vSphere HA appropriately to protect against host and virtual machine failures.

The shift to Fault Domain Manager-based HA (FDM) in vSphere 5 is transparent to vCloud Director. The total number of hosts in an HA/DRS cluster remains 32, so cluster sizing guidance for vCloud environments does not change. FDM requires a single master host, as opposed to legacy HA’s five primary nodes. If the master host fails, the remaining slave hosts participate in an election to choose a new master.

The eight hosts per cluster limitation if using fast provisioning (linked clones) and VMFS datastores does not apply to vSphere 5.1-backed resource groups. Fast provisioning on VMFS5 datastores supports up to 32 hosts.

Provider virtual datacenters represent a service offering. When building clusters, group similar servers together (number of hosts, number of cores, amount of memory, CPU type) to support differentiation of compute resources by capacity or performance.