I've been having issues with trying to upgrade my OES2015SP1 systems to OES2018 in a VMWare dev environment, I'm suspecting that my issue is due to VM factors and not the upgrade, I had another post about how I get a black screen and was pointed to a TID for reference, but that isn't why I'm here. Usually I wouldn't be concerned about having to back up my eDir for an upgrade but since I haven't been successful in my testing environment I am concerned about doing the upgrade in production and want to give myself as many safeguards as I can.

I am considering proceeding with the upgrade in production where I'm hoping that I won't experience the same issue that I get in my dev environment, and I'm here to make sure that I can cover myself in case I do experience the same problem. My plan is to take a powered off snapshot of my system to do the upgrade, but based on my experience with my trouble upgrade the upgrade process completes successfully but I experience problems when the system then tries to boot up. If I experience this it is my intention to revert my VM's snapshot, but since the directory would have been updated because the upgrade depends on being able to communicate with another server, how would I go about backing up and reverting to to the pre-2018 version of the directory objects?

I have 3 servers, 2 for GW services and 1 for File services and my primary replica is on one of the GW servers.