Re: GEOM and moving to CURRENT from 7.1

On Sun, 11 Jan 2009, George Neville-Neil wrote:

> Howdy,
>
> Beware if you are upgrading from a 7.1 system to CURRENT that you may 
> need to have the kernel options GEOM_MBR and GEOM_BSD in your kernel. 
> I spent a couple of hours dealing with this on my Thinkpad X60 today 
> which had, what I thought, was a pretty simple setup of 1 slice for BSD, 
> and a simple layout of /, swap and /usr.  When I tried to boot the new 
> kernel I got to the mount error prompt and could not mount ad4p1 or 
> anything like it. Adding the GEOM_MBR and GEOM_BSD options back into the 
> kernel fixed things. Happily I was able to boot 7.1 still and fix this.

There are several things to be aware of moving from GEOM_MBR|BSD to 
GEOM_PART_*. My label was "wrong" in gpart's eyes, and I had to relabel 
the drive with a copy of the same label (no data loss). I also have a ZFS 
root filesystem embedded in the "e" part of the slice, which was marked as 
"unused" in the label, and thus GEOM_PART_BSD created no device node in 
/dev. Changing it from "unused" to "ZFS" in the label was the solution to 
that.

Unfortunately, during the process of "fixing" the label, grub stopped 
working, leaving my system without a boot loader. In the absence of a 
bootable live cd, I had to pop out the drive and plug it in to another 
system to install the standard boot loader. Was not a fun evening!