[plug] Debian 10-11 upgrade issues

[Nick Bannon]

On Wed, Jun 28, 2023 at 10:03:54AM +0800, Dean Bergin wrote:
> I'm wondering if anyone can offer some sage advice around an issue I have
> post-upgrade of a homelab server I maintain.
> I'm stuck in emergency mode and it looks as though my LVM (device-mapper)
> mounts aren't available.

Heya, Dean! Sounds fixable, good luck. Can you boot with an "old" kernel?

While it's usually possible to get away with just the installer
"rescue" mode, I find it's more reassuring to reach for a different
"live boot" at this stage and interactively use https://www.finnix.org/
(small, Debian "testing" based, and also great for a headless server)
or https://www.debian.org/CD/live/ . Either the latest, or occasionally
going back to a version that more closely matches your current system.

Boot it, let it scan for what's available, then interactively experiment
to find exactly what you need to get your system mounted and self-bootable.

> Before upgrading, I did have crypto-mount (or something) enabled, which
> produced errors but did not prevent boot as I never encrypted the
> underlying raid block device md0 (it was always planned but never
> implemented, so it was skipped when building the server and I never
> disabled the crypto boot service).

It sounds like that specifically was "just" a harmless warning? We need
to find the errors in console output, or `dmesg`, or what's totally
missing that "ought" to be there, like a loaded working driver for your
storage hardware (`lspci`/`lshw` ?).

Maybe those devices were missing because of an `mdadm` error that
scrolled past unnoticed, or a missing driver module in the `initramfs`,
and it might be easier to see from a running live USB what was missing.

( If the LVs are missing (`lvs`/`vgs`/`pvs`), the md0
has probably not been assembled. Maybe that failed because the devices
under md0 were missing, so that needs to be fixed before `vgchange -ay`
will help. )

There may be some known relevant issues that got written down in the
"Upgrade" chapter 4 or "Issues to be aware of" chapter 5 of:
https://www.debian.org/releases/oldstable/amd64/release-notes/
https://www.debian.org/releases/stable/amd64/release-notes/

[...]
> I'm seeking some advice to try to quickly fix this before I consider
> rebuilding. I do have a copy of /etc before upgrading FWIW.

Good, could be handy to compare or know what devices or filesystem UUIDs
to look for.

Nick.

-- 
   Nick Bannon   | "I made this letter longer than usual because
nick-sig at rcpt.to | I lack the time to make it shorter." - Pascal