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 (FDM)-based HA in vSphere 5 is transparent to vCloud Director. The total number of hosts in an HA/DRS cluster remains at 32, so cluster sizing guidelines for vCloud environments do not change. FDM requires a single master host instead of five primary nodes for legacy HA. If the master host fails, the remaining slave hosts select a new master.

The eight hosts per cluster limitation for 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 (based on number of hosts, number of cores, amount of memory, CPU type) to support differentiation of compute resources by capacity or performance.