mount 2nd HD containing running Freebsd system

[RW]

On Wed, 25 Mar 2009 17:55:50 +0800
Fbsd1 <fbsd1 at a1poweruser.com> wrote:

> I have run out of space on my running 7.1 system. I have a 2nd HD 
> containing 6.1 that I want to mount and use the 80gb /usr slice.
> 
> What is the mount command to use?
> 
> Thinking   mount /dev/ad1 /mnt  but un-sure how this handles the 6.1 
> slices on that HD.

You need to mount the bsd partition[s] not the whole disk.
Probably something like /dev/ad1s1d 

I'd suggest you re-label it and put a new filesytem on it if you can.