Re: Devfs, was Re: Migrating to larger numbers

Guest section DW (dwguest@win.tue.nl)
Tue, 15 Jun 1999 20:48:50 +0200 (MET DST)


From: "Mark H. Wood" <mwood@IUPUI.Edu>

> > Maybe you don't know, but we have that today.
> >
> > LABEL=Boot /boot ext2 noauto 0 0
> >
> > and
> >
> > UUID=3e6be9de-8139-11d1-9106-a43f08d823a6 /boot ext2 noauto 0 0
> >
> > both work in fstab.

Thank you! I've been wanting this for ever so long. I was about to
complain that I'd never seen it documented, but man 1 mount does indeed
document -L and -U switches for these.

However, man fstab doesn't show any such options, and still claims to be
for Linux 0.99 from 1993. Where do I get the updated page?

Ask and thou shalt receive.

...

The first field, (fs_spec), describes the block special
device or remote filesystem to be mounted.

For ordinary mounts it will hold (a link to) a block spe-
cial device node (as created by mknod(8)) for the device
to be mounted, like `/dev/cdrom' or `/dev/sdb7'. For NFS
mounts one will have <host>:<dir>, e.g., `knuth.aeb.nl:/'.
For procfs, use `proc'.

Instead of giving the device explicitly, one may indicate
the (ext2) filesystem that is to be mounted by its UUID or
volume label (cf. e2label(8)), writing LABEL=<label> or
UUID=<uuid>, e.g., `LABEL=Boot' or `UUID=3e6be9de-8139-
-11d1-9106-a43f08d823a6'. This will make the system more
robust: adding or removing a SCSI disk changes the disk
device name but not the filesystem volume label.
...

(fstab.5 from the not-yet-released util-linux-2.9t).

The addition of these features should have been announced with much
fanfare. Did I miss something?

Well, when I added it to 2.1.116 this was just some development
kernel that not so many people used. And these kernels had all
kinds of obscure problems - not the right time to tell everybody
to start using them. Now with 2.2 this is an option that is
available. Still, only mount knows about it - it will have to be
integrated more fully before we can be completely happy.

Andries

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