Sysinstall partition oddities (6.3/i386 -> 7.x/amd64)

[Steve Polyack]

Steve Polyack wrote:
> I've seen some oddities with the partition and bsdlabel editors in the 
> sysinstall program on the 7.0 and 7.1 releases.  The partition editor 
> seems to be reading or parsing the partition table incorrectly.  I had 
> a 6.3-RELEASE system with the following layout:
> /dev/amrd3s1a on / (ufs, local)
> /dev/amrd3s1g on /opt (ufs, local, soft-updates)
> /dev/amrd3s1f on /usr (ufs, local, soft-updates)
> /dev/amrd3s1d on /var (ufs, local, soft-updates)
> /dev/amrd3s1e on /var/log (ufs, local, soft-updates)
>
> Upon booting into the 7.x install media and encountering the FDISK 
> Partition Editor, the partition it's seeing is amrd3*a*s1, as opposed 
> to amrd3s1.  Trying to continue with the partition table and bsd 
> labels as is only led to the installer bailing out.  As soon as it 
> would attempt to newfs the disk partitions, the installer would error 
> and report that it can't find a device entry in /dev for amrd3*a*s1a.  
> Since preserving the data on the disk was not critical, I was able to 
> continue by deleting the original partition/slice and recreating 
> them.  This worked fine.
>
> However, I'm still curious as to what the cause of this is.  I have 
> seen this before on two other systems while installing 7.x, quite 
> possibly while upgrading from 6.3.  When this occurred, I was also 
> moving from i386 to amd64;  Is there some kind of offset for partition 
> tables which may change based on architecture?
>
> Lastly, here's a screenshot of the partition editor: 
> http://people.collaborativefusion.com/~spolyack/fbsd-install.jpg
>
> Unfortunately, I do not have any screenshots of the errors during the 
> newfs step.  If this comes up again, I'll be sure to take some.  Thanks.
>
This also occurs in VMWare.  I'm able to get the exact same behavior by 
installing a 7.1-RELEASE system (single slice, da0s1), then booting off 
the install media and start a new installation.  It picks up the 
partition as da0as1 instead of da0s1, making it impossible to use 
sysinstall while preserving existing partitions.

-Steve Polyack