Architecting a vCloud Director Solution : Scalability : 8.1 Resource Group : 8.1.4 Scalability Across vCenter Server Systems
   
8.1.4 Scalability Across vCenter Server Systems
vCloud Director can manage up to 20 vCenter Server systems. It is possible to horizontally scale the resource group by adding additional vSphere environments. However, other systems or resource limits might impact the maximum scale.
Note Deployments from catalogs or moving/cloning vApps across vCenter Server systems results in a different copy process than within vCenter Server. The copy process within vCenter Server is handled by ESXi hosts directly through a storage network or network file copy protocol. The copy process across vCenter Server systems results in an OVF export that is staged and copied through the vCloud Director cell transfer storage. This process is much slower with a higher impact on the infrastructure (network bandwidth, vCloud Director cell compute, and transfer storage).