If you want to have 2 vcenter servers then install the 2nd one in a linked mode with the first one. You can either choose to have a single remote DB for both of them (as a downside you have single point of failure ) or have their separate remote or local DB (hence you will have redundancy against the failure of a DB of any vcenter ). If you have both the vms in the same cluster then u will have a single point of failure (what if the cluster fails, what if the separate network that you have for this cluster itself fails?) and to avoid that you might want to have both the vcenter servers on a different cluster with their different local/remote DB in linked mode with each other to offer the best redundancy possible with the least cost and worry.
IF you are talking about just 1 VC then install it on ur new setup/cluster and enable HA and if u have enough resources then u can even try enabling FT but do u need that level of redundancy if u r taking regular backups of the VC?
u r the judge since all solutions r only specific to a specific config
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