SolidNetwork So, as an update up to my post, I have now completed my v12.1 upgrade directly from v11.0.4
Everything went smoothly by following the guide:
https://enhance.com/docs/getting-started/upgrading-from-v11.html
(Also used the cPFence guide to have it uninstalled and reinstalled again after the upgrade).
The only weird behavior I noticed during the upgrade, was that you really need to stick to the guide above and do not follow echoed commands that appear in the command line, as in my case those should be executed later on in the guide.
The only lengthy process of the upgrade was the fix backup permissions command (took around 4 hours) but I guess that's normal for 200GB of files on HDD storage. But that was no issue as it did not affect the host server (App+DB). Apart from that the whole process would be completed within minutes.
Another plus is that there was no noticeable downtime on the hosted websites, less than 2-3 minutes when shuting the host server for a full snapshot and then another 2-3 minutes when restarting the server after running apt update && apt upgrade. Same goes for the mail server. The 3xDNS Role setup really payed off here. I did not have to restart the servers after the upgrade and will probably do so during the night in the next patch update.
The v12 speedup is very noticeable especially on the panel role server as I constantly had over 50% RAM load but now its always around 11% (my panel server has 12GB RAM). Also the CPU load is much more stable around 0.2 now.
I'm now monitoring the backups, first thing I noticed was that Mail backup is now separate from Files + DB. I'll post if I notice any new bugs.
