This morning's break of the server has been repaired, and all seems normal.

After a couple tries, I was able to fix the hard drive issues using a Ubuntu bootable USB.

On the first try, I only checked and repaired one disk. This got the server to boot again, but still to a read-only state.

On the second try, I checked and repaired both disks. There were repairs made, so fingers are crossed.

Further, I mounted them while running from USB and perused the drives for the right contents. All seemed still intact, although if a repair happened in a big block, like the middle of a Docker container, that might not work. Thankfully, easily replacing containers is why we use things like Docker.

I rebooted again, and the server returned! Another quick scan and fix of the firewall (and restart of Docker), and everything returned to normal.

Probably not enough coffee, or maybe an invalid fsck on the server, marked but not fixed or some such.

Back to the normal I'm used to.