[Pkg-sysvinit-devel] Bug#653073: why root filesystem reported as /dev/disk/by-uuid/ long name starting today?

[Roger Leigh]

On Sat, Dec 24, 2011 at 10:21:26PM +0800, jidanni at jidanni.org wrote:
> RL> - initramfs mount command line
> RL> - initramfs busymox mount binary
> RL> - initramfs /dev [but should be udev]
> Does your fstab have any UUID in it?

No.  I use LVM.

> We were told that's what we should use.

This is correct advice.

> Does your df(1) or mount(1) output also have none, some, or all of them?

None, due to using LVM.

> Is there a way to get back the readable sda stuff without ripping the
> UUID stuff out of fstab?
> Is the UUID stuff more readable than the short sda strings?
> I have no idea what is causing it.

This is why I asked you to investigate the origin in my previous
message.  It's likely it originates from the rootfs being mounted
in the initramfs.  If you are using an initramfs.  It's possible
that it could be corrected by tweaking the script run in the
initramfs.  But I really can't speculate here; it's something
you would need to investigate for yourself.  I mentioned potential
culprits in my previous message.  If you mount using
root= on the kernel command-line, rather than an initramfs, it may
also be the case that the UUID is the only thing available to
the kernel in early boot, and this is preserved.

Readability of the strings is not really related here.  UUIDs
are used for unambiguity when referring to a specific partition,
given that on modern systems device names are not guaranteed to
be stable.  While it would be preferable for readability to use
shorter strings, this is not strictly a bug--it's obviously
correct, just not in the most readable format.

I would suggest that you add 'break=bottom' to your kernel
command-line, and check in the initramfs whether the root
device UUID exists, and if so if it is a symlink to the
short-form device name.  I would then mount the rootfs onto
e.g. /mnt and check /proc/mounts to compare mounting the short
and long names.  I would then do the same on a normally booted
system to compare how mount behaves here.  If it's doing
something odd in the initramfs, maybe we can fix it to behave
the same as on a real system.


Regards,
Roger

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