It is obvious that backuping your data should be on top of the list all the time, but unfortunately it hasn't on mine recently and I have paid the conseguences, at least with my webserver.
I have recently converted my old Ghost website to static pages ater learning a little bit of HTML5 and looking around the code of other websites. Not that I had a lot of content but I came with a bunch of technical posts that were useful to me and I was hoping to be useful to other people dealing with OPNsense, Unbound and internet conncetions. The webserver was hosted on a FreeBSD Jail managed by the framework Bastille (which I love as it aims to bring the "Docker experience" to FreeBSD) which replaced the previous same named Jail with Ghost.
I had to reboot the Hypervisor that was managing my VMs and after booting it back up, I discovered that my webserver Jail was not listed anymore and all of it's root content was gone. I have posted the issue on Reddit but unfortunately I have not received any response and I have moved on and recreated the Jail from scratch.
Since then, I have put backups back on top of the list and moved from my previous Hypervisor to XCP-NG as it providess all of the Xenserver features for free (including automated VMs backup). I am currently backing up all of my VMs to an external NAS which it now became the Single Point Of Failure for by backapped data, but this issue would be for another future project with a redundant ZFS file server.