Increasing the number of vCenter Server instances in your Orchestrator setup causes Orchestrator to manage more sessions. Each active session results in activity on the corresponding vCenter Server, and too many active sessions can cause Orchestrator to experience timeouts when more than 10 vCenter Server connections occur.
For a list of the supported versions of vCenter Server, see VMware Product Interoperability Matrix.
You can run multiple vCenter Server instances on different virtual machines in your Orchestrator setup if your network has sufficient bandwidth and latency. If you are using LAN to improve the communication between Orchestrator and vCenter Server, a 100Mb line is mandatory.