Adding partitions to gmirror device

[Jerry McAllister]

On Tue, Jan 27, 2009 at 01:49:36PM -0500, Vladislav Sekulic wrote:

> Thanks, Wojciech and Jerry, for your help.
> 
> Quoting Jerry McAllister <jerrymc at msu.edu>:
> 
> >First of all, you say that you have allocated 27GB of 238GB available.
> >Is that 238GB in the existing slice - gm0s1 or is it outside of
> >that slice?   (NOTE, the 's' in the device name stands for slice -
> >so it is slice 1 of a possible 4).
> >
> 
> It's 27GB used within the existing slice; gm0s1 spans the entire disk.
> 
> >It could be helpful if you posted you  /etc/fstab  file and also
> >what is printed if you do:    bsdlabel gm0s1   or, if it is what
> >they call 'dangerously dedicated'  do:  bsdlabel gm0
> >
> 
> $ sudo bsdlabel /dev/mirror/gm0s1
> # /dev/mirror/gm0s1:
> 8 partitions:
> #        size   offset    fstype   [fsize bsize bps/cpg]
>   a:  1048576        0    4.2BSD     2048 16384     8
>   b:  8320016  1048576      swap
>   c: 488375937        0    unused        0     0         # "raw"  
> part, don't edit
>   d:  2097152  9368592    4.2BSD     2048 16384 28528
>   e: 10485760 11465744    4.2BSD     2048 16384 28528
>   f: 41943040 21951504    4.2BSD     2048 16384 28528

OK.   Based on this you can just do the    bsdlabel -e /dev/mirror/gm0s1
as root (or from the fixit)  and then, right after the definition of 
the 'f:' partition make an 'h:' partition with '*' as both size and offset.
eg.
    h:       *        *     4.2BSD     2048 16384 28528

Write and exit from the edit session and then newfs the new partition
and fix up your /etc/fstab - the real one, not the fixit one
so it will mount where you want it - don't forget to make the mount point.
It should work just fine.   

Note, that when you are running from the fixit, it makes a filesystem
in memory and mounts that as root (/).   Your real root from the disk
will probably be in  /dev/mirror/gm0s1a  so you will need to make
a mount point in the memory root, let's say  /tmproot and mount to
that and then edit that fstab.    eg

Boot from fixit - get that holographic shell going

  bsdlabel -e /dev/mirror/gm0s1
    Do the editing, write and quit
  mkdir /tmproot
  mount -w /dev/mirror/gm0s1a /tmproot
  cd /tmproot/etc
  vi fstab
    fix it up, write and quit

Pull the CD, reboot and things should be just fine.

My only concern is, I have never used the fixit on a mirror.
I presume it should look just the same, but who knows, it might
have a different looking address.    I hope the gmirror stuff 
works on the fixit.   If not, you will need to make a boot on
something else - another hard disk with a full system.

////jerry
> 
> >If it is all in that gmos1 slice, then just use bsdlabel on that
> >slice to add the rest to another partition within that slice.  Just
> >boot from something other than that mirror, make sure nothing
> >in gm0 is mounted and then do:   bsdlabel -e gm0s1  and fix it
> >up as needed.
> >
> 
> Great, makes sense.  I'll boot from the FreeBSD livecd and do this.
> 
> Thanks again!
> Vlad
> 
> --
> Vladislav Sekulic
> Research Computing System Administrator
> Systems and Networks Research Group
> Dept. of Computer Science, University of Toronto
> http://www.cs.toronto.edu/~pocsys
> 
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