re-fdisk'ing a partition - permission denied?

[Darren Pilgrim]

On 2003.09.08 14:54:37 -0700, Jason Stone <freebsd-current at dfmm.org>
wrote:
> > You have hit one of the main issues still to be resolved in GEOM. (I
> > don't know that phk thinks it's a problem to be resolved or a
> > feature to be documented.)
> > 
> > In any case, since GEOM was added you can no longer slice or label
> > an active device.
> 
> Ah - is that to say that, in general, you can't mess with the disk's
> MBR?

You can get around the safety measure that prevents writes to active
disk devices by turning on bit 4 of kern.geom.debugflags.