Currently we have two vcenters which is connected into vROPs. If we consolidate those two vCenters into 1 so all the ESXi/VMs are in a single vCenter what happens with all the performance data that was in vROPs. Is it lost or is it retained as its all the same ESXi Hosts/VMs?
I think yes and no... 🙂
Yes - the data is tied to the solution. In your case the Cloud Account vCenter. As long as you don't delete that, the (historical) data will be retained.
No - There is a setting: global settings -> object history -> delete days
I also believe you will have those ESXi hosts double in vROps as well. One from the old solution with the old data and one with the new data.