shrinking of FreeBSD root partition on GPT

Coert lgroups at vlymskerp.net
Sat Nov 8 14:11:51 UTC 2014


On Saturday 08 November 2014 14:06:43 Arthur Chance wrote:
> On 08/11/2014 10:58, Coert wrote:
> > Hello all!
> > 
> > Just installed FreeBSD on my home server, (used to be linux)
> > 
> > When I did the installation, I used the installer defaults, and it gave me
> > the following:
> > gpart show ada0
> > =>       34  488397101  ada0  GPT  (233G)
> > 
> >           34        128     1  freebsd-boot  (64K)
> >          
> >          162  480247680     2  freebsd-ufs  (229G)
> >    
> >    480247842    8149292     3  freebsd-swap  (3.9G)
> >    488397134          1        - free -  (512B)
> > 
> > I would like to shrink my root partition, (GPT partition 2).
> > After reading through the handbook, I can adapt to shrinking instead of
> > growing,
> > 
> > What I am going to try is:
> > 1. Boot from LiveCD
> > 2. do a dump -0 of the current root partition
> > 3. delete the root GPT partition, and create a new smaller GPT partition.
> > 4.do a newfs on the new slice, and restore the dump.
> > 
> > Do I need to restore any bootcode after this? I read about bsdlabel, but
> > that seems to be only for MBR scheme?
> > 
>  > Will this work? or did i miss a step?
> 
> The two levels of bootcode are in the PMBR and partition 1, so resizing
> partition 2 shouldn't affect it. You can always use gpart bootcode to
> reinstall if you're worried.
> 
> > When that is done, I will create a freebsd-zfs partition in the freed
> > space on the disk. (Will rather still keep freebsd root on UFS)
> 
> If you don't delete the swap partition and recreate it immediately after
> the shrunken root partition you're going to be creating a GPT table
> that's out of order with respect to partition locations. I have
> absolutely no idea whether this is legitimate, but even if it is I
> wouldn't personally risk it as you can't guarantee all software will
> allow for it.
> 
> On a slightly different subject, are you using GPT partition labels? If
> not, it might be worth reading Warren Block's excellent article about
> them here
> 
> http://www.wonkity.com/~wblock/docs/html/labels.html

Thank you! I am implementing the labeling now.

Kind regards,
Coert
> 
> 
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