what is UUID naming for devices?

[David Koski]

On Sunday 08 July 2007 12:01, SteVe Cook wrote:
> Ari Sarkar wrote:
> > Hi all,
> >
> > I use ubuntu (and recently dual-boot with debian) since April this year.
> > I don't use windows anymore, in fact i don't need to. I've learned a lot
> > in Linux in these days.
> > Recently I found in ubuntu "/etc/fstab", some UUID for my mounted
> > partition rather than "/dev/sda1" etc.
> >
> > I found in internet that it has some advantages.
> >
> > My question: I have a common partition for data (xfs formatted) which I
> > want to access from both ubuntu and debian. And that partition should
> > also automatically mount at boot with user can read/write without going
> > sudo.
> >
> > How can I achieve this using UUID naming at "/etc/fstab"?

Replace the device in /etc/fstab (e.g. /dev/sda1) with UUID=<uuid_of_device>.

> > my current disk structure:
> > /dev/sda1: reiserfs (ubuntu)
> > /dev/sda2: swap (common)
> > /dev/sda3: reiserfs (debian)
> > /dev/sda4: xfs (common accessible partition)
> >
> > right now my fstab has the following line for xfs partition, what should
> > I change ?
> > /dev/sda4       /media/xfs      xfs     defaults    0  1
> > v
>
> Can't really see any great advantage myself, just a lot of fiddling
> around when a new hard disk is added. But

It can be a big advantage.  In cases where boot order changes, especially 
depending on which devices are attached, it makes all the difference in the 
world.  Another advantage is in using UUIDs for bootable flash devices as the 
device can vary depending on what it is booting on.  Using UUIDs corrects 
that problem.

> vol_id /dev/sda4

Unless /lib/udev is in your path you will probably have to use:

/lib/udev/sda4

<snip>

David