On 18/01/2022 20:00, Phil Turmel wrote:
Firstly, given that superblocks seem to disappear every now and then,
does anybody have any ideas for something that might help us track it
down? The 1.2 superblock is 4K into the device I believe? So if I copy
the first 8K ( dd if=/dev/sda4 of=sda4.img bs=4K count=2 ) of each
partition, that might help provide any clues as to what's happened to
it? What am I looking for? What is the superblock supposed to look like?
Well, I've gone to the kernel code for the structure definition a few
times, but never really got much out of it that mdadm -E didn't supply.
Well, I was hoping if I looked at it with a hex editor, and knew what I
was looking for where, I might get a clue ...
Those seem to be missing from your mail, at least for the still-working
drives....
Wait: they're gone from all three?
mdadm --examine ...
No md superblock detected
Ouch!
And no, all the stuff I tell people they should do, I haven't ... I had
so much grief with systemd, and dm-integrity, and getting stuff working,
that I never got round to being sensible ... :-(
Cheers,
Wol
