This article defines the maximum limit of ESXi host and virtual machine used with the embedded vPostgress database in a Windows installed vCenter Server 6.0.
VMware vCenter Server 6.0.x
The ESXi host and virtual machine limits are increased in vCenter Server 6.0 with the vPostgres database to 20 hosts and 200 virtual machines. This is an increase from the 5 hosts and 50 virtual machines supported in vCenter Server 5.x with the embedded Microsoft SQL database.