Hi
You get the warning because a vCenter only supports a 1:1 relationship with a vRops. Where as vRops support 1:many. The reason there's a 1:1 releastionship, is that when you in the webclient click action on an object and choose the open in vrops options, there can only be one vRops.
The last registered vRops to a vCenter gets the option for the vCenter. But it can be overridden manually.
But you can just contiue from the warning and both vRops will colled data. So that is not a problem.
There is the option to enabled HA, but placing a vRops node i each datacenter isnt supported afaik and there are some very string guide for supporting a vRops platform, in terms of latency. See the sizing guide for that.
Hope this helps.
