If you need to work with multiple vCenter Server instances or if you want to manage a number of hosts or VMs that exceed the maximum supported by a single vCenter Server instance (2,000 hosts or 25,000 powered on VMs), you can install the vCSA in ELM that allows you to connect multiple vCenter Servers together for a maximum of 15 instances.

To enable ELM, the vCenter Server instances must be registered to the same PSC in order to share roles, permissions, licenses, policies, and tags:

To install a vCenter Server in ELM, you must first deploy the PSC creating a new SSO domain or joining an existing SSO domain (another PSC instance must have deployed). Deploy the first vCSA with an external PSC instance pointing to the previous installed PSC. To configure a new vCSA instance in ELM, you just need to point the vCenter Server instance to the same PSC used before (repointing a vCSA to another PSC has been discussed previously in this chapter):