Re: FreeBSD/powerpc64 (POWER9) with ZFS on /

Sean Bruno <[email protected]> Mon, 5 Nov 2018 08:40:09 -0700
Newsgroups	gmane.os.freebsd.devel.ppc
Message-ID	<[email protected]>

On 11/5/18 2:45 AM, Piotr Kubaj wrote:
> ZFS is by default not available for partitioning in bsdinstall. We can,
> however, use manual partitioning in shell to make ZFS partitions.
> 
> But what if we want to do ZFS on /? This is currently not supported
> out-of-the-box. The reason is that Petitboot, used on POWER9 to boot
> kernel, doesn't support loading modules (at least when booting FreeBSD).
> ZFS is by default distributed only as a module, to overcome licensing
> issues.
> 
> There are two ways to boot ZFS on root with Petitboot:
> 1. We can use initramfs, which will load necessary modules. It's said to
> be supported on FreeBSD/powerpc64, but no one knows how to create one
> for FreeBSD :)
> 2. We can actually compile a custom kernel with ZFS in it (not as a
> module). This the approach that I use. Unfortunately, I can't
> redistribute this kernel, because of ZFS's license. I created a custom
> installation iso, which uses my kernel with ZFS included.
> 
> Here are the steps to do it (on an installed powerpc64 system, but
> should be possible on other architectures after redefining TARGET and
> TARGET_ARCH):
> 1. cd /usr/src/sys/powerpc/conf
> 2. cat << EOF > ZFS
> include GENERIC64
> options ZFS
> EOF
> 3. cd ../../../
> 3. make buildworld buildkernel KERNCONF=ZFS
> 4. cd release
> 5. make release
> 
> When it's done, there will be iso files in
> /usr/obj/usr/src/powerpc.powerpc64/release.
> 
> You can use it to install ZFS on root.
> 
> Note that you need a FAT32 partition to mount on /boot.
> This partition needs to have /boot/etc/kboot.conf file, with a line like:
> FreeBSD='/kernel/kernel kernelname=/boot/kernel/kernel
> vfs.root.mountfrom=zfs:zroot/ROOT/default'
> 
> You also need the appriopriate /etc/fstab:
> /dev/nda0p1     /boot           msdosfs rw      2       2
> 
> Other than that, howto at
> https://wiki.freebsd.org/RootOnZFS/GPTZFSBoot#Create_Partitions (from
> point 2., omit 1.) is totally ok to follow.
> 
> Thanks to mmacy for informing me about this little trick with including
> ZFS to kernel.
> 


I'd recommend adding a default to the kboot.conf so that your machine
doesn't hang at petitboot forever.

# cat /mnt/etc/kboot.conf
default=FreeBSD_boot
FreeBSD_boot='/kernel/kernel vfs.root.mountfrom=zfs:zroot
kernelname=/kernel/kernel'

The Power8 machines in the freebsd cluster use a statically built kernel
with no modules.

sean
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