Re: LVM and devfs (I'm intrigued)
On Mon, Mar 08, 2004 at 08:01:16PM +1000, Andrew Pollock wrote:
> On Mon, Mar 08, 2004 at 09:42:38AM +0000, Patrick Caulfield wrote:
>
> [snip interesting stuff]
>
> >
> > That's interesting.
> >
> > It was always the case that if you have devfs in the kernel but not
> > mounted, the partition names in /proc/partitions showed devfs names rather
> > than "normal" /dev/sda* type names. LVM can't reconcile those names at all
> > so it will refuse to create VGs, saying it can't find the devices.
>
> Okay, AFAIK the kernel d-i boots with for the installation process *doesn't*
> have devfs enabled, so this could explain why the initial VG and LV creation
> works...
OK, that makes sense then. LVM should be able to find already extant LVs
regardless of the devfs status, that message only really applies to creating VGs
or adding new disks to existing VGs. I suppose I could change the message but I
hadn't really bargained for someone creating the VGs with one kernel and then
using them with another, and the message is long enough as it is !
> > I must confess I haven't tried this for some time, I know for sure that
> > the LVM code that deals with this hasn't changed. (very little of LVM1 has
> > changed for ages now and it's going to stay that way). But then, it also
> > seems very unlikely that devfs has changed here either. I'll have a look
> > at it some time and see if I can find out what's happening because it
> > certainly didn't work (I remember a flurry of bug reports about it!)
> >
> >
> > So, it's not a random time-bomb. If it works then it won't cause any
> > corruption or later problems
>
> That's good to know. If I can provide any further diagnostic information for
> you, let me know. I only run stock Debian kernels, and I'm happy to hose my
> desktop again, as it's only freshly installed from last night, so it's no
> big loss. I can do a non-mirrored non-devfs install if you like.
>
> I can confirm that /proc/partitions contains devfs names presently, and I
> don't have devfsd running or devfs mounted.
That sounds reasonable, I can't see it happening that simply mounting devfs
would change the names in /proc/partitions!
If it's definitely true that the kernel used to create the VGs has no devfs in
it, then that explains what's happening - and I'm happy it should all work fine.
--
patrick
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