On 2019-10-24 06:41, Christian Pernegger wrote:
I must admit, this discussion is going (technical) places I don't know
anything about, and much as I enjoy learning things, I'd rather not
waste your time (go make btrfs better! :-p). When all is said and done
I'm just a user. I still don't understand how (barring creatively
defective hardware, which is of course always in the cards) a crash
that looked comparatively benign could lead to an fs that's not only
unmountable but unfixable; how metadata that's effectively a single
point of failure could not have backup copies designed in that are
neither stale nor left to the elements, seems awfully fragile -- but I
can accept it. Repair is out.
Recovery it is, then. I'd like to try and build this rescue branch of
yours. Does it have to be the whole thing, or can btrfs alone be built
against the headers of the distro kernel somehow, or can the distro
kernel source be patched with the rescue stuff? Git wasn't a thing the
last time I played with kernels, a shove in the right direction would
be appreciated.
Trying to build the module by itself against your existing kernel is
likely to not work, it's technically possible, but you really need to
know what you're doing for it to have any chance of working.
Your best option is probably to just pull down a copy of the repository
and build that as-is. Most distros don't strictly depend on any
specific kernel patches, and I'm fairly certain that Mint isn't doing
anything weird here, so unless you need specific third-party kernel
modules, you shouldn't have any issues.
Relapse prevention. "Update everything and pray it's either been fixed
or at least isn't triggered any more" isn't all to
confidence-inspiring. Desktop computers running remotely current
software will crash from time to time, after all, if not amdgpu then
something else. At which point we're back at "a crash shouldn't have
caused this". If excerpts from the damaged image are any help in
finding the actual issue, I can keep it around for a while.
Disaster recovery. What do people use to quickly get back up and
running from bare metal that integrates well with btrfs (and is
suitable just for a handful of machines)?
Backups, flavor of your choice. I used to use AMANDA, but have recently
become a fan of borgbackup (other than it's lack of parallelization
support, it's way more efficient than most other options I've tried, and
it's dead simple to set up). I store enough extra info in the backup to
be able to rebuild the storage stack by hand from a rescue environment
(I usually use SystemRescueCD, but any live environment where you can
get your backup software working and rebuild your storage stack will work).
The trick here is not to ask 'what integrates well with BTRFS', but
instead 'what doesn't care at all what filesystem I'm running on', and
then find something that works for you to replicate whatever special
layout requirements you have.
