Re: "WARNING: device 0 not present" during scrub?

The modules are in the kernel, the progs are in the main archive, it's
an option in the installer. It's not the default fs but I couldn't
find any indication that it's more or less supported than, say, xfs.
Why they've chosen 3.16 (and not 3.18, which would be a long term
release) I don't know, but the fact remains that that's the default
kernel of a tier 1 distro, so people using it are going to be around
for a while.

quoted

But absolutely, of course we hope the problem is gone with the newer
version, *that's how file system development works.*

Be that as it may, as I said, that approach doesn't inspire
confidence. If I had the vaguest idea about how to reproduce it, sure,
but all I have is an apparently lightly corrupted or at the very least
glitchy fs (it mounts and unmounts just fine). How would I know if a
new kernel helped things?

Boot the board with one of these images (a live one I would say):
http://download.opensuse.org/tumbleweed/iso/
This weekend this is kernel 4.4.0-2-default and tools 4.3.1

Then report back the result of btrfs check of the fs

You might get some (or millions) false positives from the check with
tools 4.3.1 (but fixed in v4.4), due to the tools version your fs is
created with. This is not a problem, at least is my experience.
But you can compile the v4.4 tools from
https://github.com/kdave/btrfs-progs