Hi
I can confirm that the NethServer (rarely) needs a repair, and when it does, xfs_repair on an unmounted system WORKS !!!
XFS will not do an automatic FS-check like Ext4 does during boot. (I still consider XFS better than Ext4 in almost all cases).
Doing a Proxmox image before is prudent (My NethServers run almost ALL in Proxmox), otherwise a clone with eg clonezilla is a very good (and safe) idea.
I use SystemRescueCD, that has sofar worked well (3 times used on different servers).
Here, LVM is recognized from the start, you only need to run this:
xfs_repair /dev/mapper/VolGroup-lv_root
This is fairly fast, even for a large filesystem.
Note: After the power outage which caused this at one of my clients, the client finally bought a new UPS (The old one had died a year earlier at 11 years of age)!
My 2 cents
Andy