UUIDs in fstab

[Patrick O'Callaghan]

On Wed, 2008-04-30 at 12:30 -0700, Andrew Farris wrote:
> Patrick O'Callaghan wrote:
> > On Tue, 2008-04-29 at 22:40 -0700, Andrew Farris wrote:
> >> Chuck Anderson wrote:
> >>> On Wed, Apr 30, 2008 at 12:35:41AM -0400, Christopher L Tubbs II wrote:
> >>>> Granted, I understand that a UUID is just as good as a LABEL, as far as 
> >>>> functionality goes, but LABELs are so much easier to read, compare, and 
> >>>> type. Why would the F9 installer choose to create UUIDs instead of readable 
> >>>> LABELs? I have no idea.
> >>> UUIDs are unique.  LABELs may not be.
> >> This is precisely the reason, because the realization has hit people that a 
> >> system may have many linux distros installed on it, so labels made by other 
> >> distros for '/' are not unique; at the same time the device names are no longer 
> >> guaranteed to be in any particular ordering when some devices come and go 
> >> (hotswapped drives especially).  UUIDs are the identifier that won't get mixed 
> >> up or changed.
> > 
> > It seems to me that there are two issues here:
> > 
> > 1) How do I identify my disks/partitions so I know what's going on?
> > 2) How do I tell the system what to mount where in a consistent manner.
> > 
> > Labels solve 1 but may fail at 2. UUIDS solve 2 but are awkward for 1.
> > 
> > So, off the top of my head, why not use both? It's trivial for the
> > system to notice when two partitions have the same label, so at install
> > time (or mount time, or whatever) it could simply offer to change one of
> > them, e.g. if I have LABEL=foo on two partitions, relabel them foo-1 and
> > foo-2. Keep the UUIDs but make the labels work for the humans among us.
> 
> The problem does not only arise at install time.  In fact, thats the simple 
> case.  If you move a disk from system to system you could get it booting the 
> wrong system because labels conflict, when during install it was fine.  So you 
> need to make sure when two systems are installed their labels will be 
> sufficiently unique... foo-UUID might work fine for that but anything short of 
> it fails.

Again, this can be dealt with by an error message or dialogue. The
system notices the conflict and reports it: "Partitions x and y have the
same label. Please relabel one of them to proceed." The corner case is
if I remove one hd and replace it with another one with the same label,
but IMHO if I do that it's because I *want* to do it, e.g. replace a
failing drive with a new one, something which is currently hard (or at
least messy) to do using UUIDs.

poc