Re: [gentoo-user] General weirdness - a tale of woe.

[Todd Goodman <tsg@bonedaddy.net>]

* Rich Freeman <rich0@gentoo.org> [150528 08:45]:
> On Wed, May 27, 2015 at 8:01 PM, Peter Humphrey <peter@prh.myzen.co.uk> wrote:
[..SNIP..]
> UUIDs are often preferable in these kinds of configurations, because
> you're less likely to run into duplicate identifiers, they don't
> change, and so on.  If I mount root=UUID=foo, then my initramfs will
> try really hard to find that partition and mount it.  If I mount
> root=label=foo then it will still try hard, but if for some reason I
> have more than one device with that label I could end up booting from
> the wrong one.  If I mount root=/dev/sda1 then my boot may fail if I
> add a new drive, if the kernel behavior changes, if the udev behavior
> changes, and so on.
> 
> I don't believe either the kernel or udev makes promises about device
> names being stable.  It often works out this way, but it isn't ideal
> to depend on this.
> 
> -- 
> Rich

It's worse than just getting the wrong filesystem mounted if the wrong
filesystem gets mounted as /tmp.

OpenRC's bootmisc will wipe the /tmp directory at boot (and likely
systemd as well, but I haven't checked.)

This means if disk device names get shifted and something other than the
proper /tmp device gets mounted as /tmp then it's "restore-from-backups"
time.

This happened to me and wiped /home (the /dev/md* devices got renumbered
once.)

So I've switched to UUID mounts so that problem doesn't happen in the
future.

It's really unpleasant if that happens.

Todd