I currently have a 5.1.0 and a 6.0.0 hosts. (home lab)
I plan on setting up a new one sometime in the fall or next year likely running latest of 6.x or 7.x, to be decided at that time.
Now, I got the DC version and it has 2 keys. I see I also have access to the PRO version.
I haven't set up any license keys yet.
I was thinking of activating a key on 6.0 and then the second one on the new host whenever that will happen, and have the 6.0 one remote backup the 5.1.0 VMs.
Is this something that can be achieved? Or should I rather install the PRO version of the 5.1? I've read a bunch of things today and am a bit confused as some articles were mentioning to not mix different esxi versions together with the same install of xsi backup.
I cannot upgrade 5.1 because it is heavily using PCI passthrough in a few VMs and 6.0 just doesn't support some of the hardware of that server (already tried and was not able to get some of the stuff to pass trough, so gave up on it).
I may be able to upgrade the current 6.0 top whatever the new server will be since I'm not using PCI passthrough (yet), however I am expecting that one to get a bit or more outdated hardware wise and not have supporting drivers anymore at that time (or maybe at a later time).
So long story short, I am expecting to have 3 different versions of esxi on the servers at some point in time.
So my question would be, how to properly plan on backing all these up with this 2 key DC version and the apparent access to some PRO licenses? What would be the best approach?
Well, we don't know what to answer. There isn't a better approach other than considering that Pro Classic is not compatible with (c)ESXi 7.0. Any other consideration is up to you, there's nothing we could add.