bsdlabel partiton c error message on new install

Jeremy Chadwick koitsu at
Tue Oct 21 10:15:15 UTC 2008

On Tue, Oct 21, 2008 at 10:42:06AM +0100, andys wrote:
> Hi Ulf, 
>  thanks a lot for your answer, previously I'd asked this question on the  
> freebsd-questions list and someone suggested asking it here as they didnt 
> know the answer, however I did get pretty much 2 responces telling me to  
> reinstall the OS!! :S 
> For example I had this answer: 
> l 
> So I assume you would disagree with this and the other person who advised 
> me this was a serious error? And if this actually isnt a problem, does 
> bsdlabel need to be updated (and the man page) to reflect the fact this 
> can be seen on a healthy system? 

Part of the problem is that you're "tinkering with bsdlabel" when most
users simply create slices and partitions and don't bother to look at
the results -- they build it all, install, and don't worry about it.
I'm sure if ran bsdlabel and saw what you did, I'd be concerned too, so
you did the right thing by asking.  All the systems I maintain have the
c slice offset at zero, but Ulf's explanation makes perfect sense.  (I
believe even Windows does something similar to this, except it leaves
the leftovers at the end of the partition table for alignment.)

Comparatively, there's the silly "cylinder geometry" warning that
sysinstall spits out prior to launching into slice manipulation.  It's
silly in the majority of cases, but apparently it's legitimate when it
comes to older/smaller disks, particularly SCSI.  That said, you should
see the look on Linux users' faces when they see it -- a look of fear,
followed by someone saying "You can ignore that", followed by "...then
what the hell is the point of printing it?!!"  :-)

| Jeremy Chadwick                                jdc at |
| Parodius Networking              |
| UNIX Systems Administrator                  Mountain View, CA, USA |
| Making life hard for others since 1977.              PGP: 4BD6C0CB |

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