GPT Support on Freebsd

Wed Oct 29 16:51:35 PDT 2008

More news :

1) Boot from the livecd pcbsd
 	- Like I remember, pcbsd shows me only the first four partitions in the 
installation wizard. That's correspond to the partitions which are 
synchronised from the gpt by refit.
	- When I boot to emergency mode, I am able to access to all my partitions ! 
and a "gpt show ad0" works fine. But, still from the emergency mode, I chroot 
in my pcbsd root partition, I can't see the gpt anymore. Pretty weird...

2) New kernel
Like I said, I recompile a kernel from the generic with two more lines :
"options         GEOM_PART_MBR"
"options         EXT2FS"
When I booted on it, I had a problem : ad0 became ad5. So the mountroot asked 
me to enter the name of my root partition and Miracle ! it show me ALL my gpt 
partitions, include my Home in ext2.

Then I enter "ad5s4a" which is my pcbsd root partition.
After the boot, I thought all was fixed but no, I still can only see the 4 
first partitions in the /dev and "gpt show ad5" still returns an error.

It's pretty weird because before the mount of the root partition, i was able 
to see all my gpt partitions, then after, the problem remains.

I don't enough know the freebsd boot process to understand by myself. Any 
Ideas ?

Franck

> Hi,
>
> Thank you for help. I provide you the maximum information about my
> partitions.
>
> Before, I watch the kernel configuration. When I fetch the kernel
> sources, I can see 2 differents configuration files : DEFAULTS and
> GENERIC. and the line : "options         GEOM_PART_GPT" is present
> only in GENERIC. If I use my knowledge in linux systems, I would say
> that my actual kernel was compiled with the DEFAULTS conf, which
> doesn't enable the support of GPT for GEOM. Maybe I'm wrong, my knew
> kernel is compiling...
>
> On Freebsd :
>
> [Dante at iris-bsd /usr/home/Dante]$ ls /dev/|grep ^ad
> ad0
> ad0s2
> ad0s3
> ad0s4
> ad0s4a
> ad0s4b
> ad0s4c
>
> my dmesg :
> http://pastebin.com/m7b5f130e
>
> On Gentoo :
>
> dante at iris:~ % LANG=C sudo parted /dev/sda
> GNU Parted 1.8.8
> Using /dev/sda
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted) p
> Model: ATA ST9200420ASG (scsi)
> Disk /dev/sda: 200GB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
>
> Number  Start   End     Size    File system  Name                  Flags
>  1      20.5kB  210MB   210MB   fat32        EFI System Partition  boot
>  2      210MB   19.4GB  19.2GB  hfs+         MacOSX
>  3      19.4GB  19.6GB  206MB   ext2
>  4      19.6GB  39.5GB  19.9GB
>  6      39.5GB  42.7GB  3142MB  linux-swap
>  5      42.7GB  58.4GB  15.7GB  ext3         Gentoo
>  7      58.4GB  74.1GB  15.7GB  ext3
>  9      89.9GB  200GB   110GB   ext3
>
> The 4 is my ufs partition. UFS is not recognize on my gentoo system.
> The partition 7 is my home, the one that I want to mount under
> freebsd.
>
> Again, thank you for your help
>
> Franck
>
> 2008/10/29 John Baldwin <jhb at freebsd.org>:
> > On Wednesday 29 October 2008 11:52:19 am Franck Royer wrote:
> >> John Baldwin a écrit :
> >> > On Wednesday 29 October 2008 07:42:18 am Lowell Gilbert wrote:
> >> >> Franck Royer <royer.franck at gmail.com> writes:
> >> >>> Can I oblige pcbsd to look the gpt table instead of the msdos one ?
> >> >>> How can I access to my fifth partition ?
> >> >>
> >> >> John Baldwin (jhb) has been working on GPT support, but it's still
> >> >> reported to be a work in progress. It works as far as recognizing
> >> >> disks over 16TB.  It also gets picked up by the geom framework.  I'm
> >> >> not sure about booting, although there are tantalizing hints in the
> >> >> manual pages.
> >> >
> >> > GPT booting works just fine on 6.x and later.  Using the gpt(8)
> >> > utility
> >
> > you
> >
> >> > basically do:
> >> >
> >> > # gpt create foo0
> >> > # gpt boot foo0
> >> >
> >> > The second command creates a special boot partition in /dev/foo0p1. 
> >> > You
> >
> > can
> >
> >> > then add partitions:
> >> >
> >> > # gpt add -t ufs <other params like size if needed> foo0
> >> > # newfs /dev/foo0p2
> >> >
> >> > gpart(8) in HEAD works similarly.  The one thing lacking is that
> >> > sysinstall/libdisk doesn't handle GPT, so there isn't a nice way to do
> >> > it during installation.
> >>
> >> Ok thank you. But actually, it's not what I'm looking for.
> >>
> >> I use freebsd on a macbook. On this macbook, I already have a gpt,
> >> refit, mac os x and some linux partitions. The problem is freebsd, which
> >> doesn't recognize partitions after the fourth one (but my gentoo linux
> >> see them).
> >>
> >> Then, I suppose freebsd use the mbr partition table (synchronized from
> >> the gpt one using refit) to populate the /dev, but partitions after the
> >> fourth, which are those I want to use, are only indexed in the gpt.
> >>
> >> Finally, I want to force freebsd to use the gpt on my hard drive to
> >> allow it to see others partitions.
> >>
> >> I don't want to destroy my actual gpt, maybe one day, but no right now.
> >>
> >> Tell me if my english is too bad to be understood.
> >>
> >> I just want to precise that I use pcvbsd 7.0, so the kernel
> >> configuration might be different than the freebsd generic one.
> >
> > What device entries do you see in /dev?
> >
> > --
> > John Baldwin
>
> --
> Franck Royer
>
> Student of Manchester University
> Etudiant Ingénieur de l'ENSIIE (Ecole Nationale Supérieure
> d'Informatique pour l'Industrie et l'Entreprise)
>
> e-mail/jabber: royer.franck at gmail.com