I currently have no email access through my usual email address; thus I am
resorting to gmail.
The server was working fine last night, until:

Last night my server became completely nonresponsive. It was inaccessible
through wifi, and it wouldn't respond to keyboard input. Its screen
remained black.
But it seemed to be busy, judging from its blinking hard drive light.

I rebooted it by the power button. This was a hard reset.

Subsequently it refused to boot. It stalled in the initrd, claimint that I
eeded to manually fsck the root partition.

So I entered the appropriate fsck command from the keyboard, checking it
twice, and leaving out the -y so that in case I made a mistake it shouldn't
screw anything worse than it was already. (If successful I planned to redo
it with the -y)

But fsck reported it could not find the partitoin it was to check.

It was an lvm partion on a RAID.  (fsck can handle that, right?  Or did I
do it wrong?  Something like
    fsck /def/dm-1/VG1-long-name
into the (initramfs) prompt.
)

I also did an ls on that partition. That worked, except the top-level
directory listing was gibberish.

At this point I figured the root partition wa throroughly borked. that was
probably what the server was busy with when it went unresponsive -- borking
the root partition.

Any advice at this point?

Next I figure it's time to wipe that partition, create a new one in that
place or elsewhere, and and restore it from backup. Yes, I have a recent
backup! (unusual for this kind of question)

But without booting, that won't work,

* Approach 1: Get a copy of refracta, and boot from that.

So I downloaded
https://get.refracta.org/files/beowulf/refracta10.6_xfce_amd64-20211226_1733.iso
and dd'd it to /dev/sdc1 . (Is that the way to do it?)
before using it on the server, I decide to try booting from it on my
laptop, just to rule out one thing that went wrong.

(yes, I used the beowulf version to reduce any incompatibilities that might
arise between different releases of Devuan, not that I expected any)

I told the laptop to boot from USB, booted, and it complained it could not
find any boot medium. Evidently not copied correctly, or wrong kind of
boot record.

(my laptop and server are both, as far as I've ever known, BIOS machines).

Any further advice?

I have no website, and no access to my email system until this is resolved.

* Approach 2:

(not tried yet)

Remove the relevant hard drive from the server and connect it to my laptop
with as USB/SATA adapter and mess with it that way.
I'll have to activate the RAID on my laptop (how?) to process that drive
properly. Should be OK, since the RAID is currently defective, and there's
another drive on my table that hasn't been activated yet, and it's a
defective RAID with only one drive.

Any other ideas?

-- hendrik