How to predict drive number change for 7.3->8.1 upgrade?

Maciej Milewski milu at
Fri Sep 17 15:54:18 UTC 2010

Dnia piątek 17 wrzesień 2010 o 16:35:52 Michael Sperber napisał(a):
> "Marat N.Afanasyev" <amarat at> writes:
> > you may try the following commands:
> > 
> > sysctl kern.geom.debugflags=16
> > 
> > foreach fs (your-filesystems)
> > glabel label your-$fs-label your-$fs-device
> > end
> > 
> > echo geom_label_load="YES" >> /boot/loader.conf
> > reboot
> > 
> > and see if the labels appear in /dev/label
> Is this safe to do?  The man page for glabel seems to imply that glabel
> should be used before newfs, and tunefs after newfs.
It's because geom class uses the last sector of the provider to keep his 
metadata, so if you will overwrite this sector then you lose this metadata(in 
this case label). So to not lose this metadata you should use geom_label first 
and then newfs on the /dev/label/...
I think that using ufs label should be sufficient, glabel supports them too 
(under /dev/ufs directory).


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