Updating to 13-stable and existing ZFS pools: any gotchas?

[Dean E. Weimer]

On 2021-03-17 9:59 am, tech-lists wrote:
> On Sun, Mar 14, 2021 at 09:59:21AM +0100, Stefan Bethke wrote:
>> I'm planning to upgrade three production machines with existing ZFS 
>> pools to 13-stable. Is there anything I need to pay attention to wrt 
>> OpenZFS? Or should it be fully transparent, apart from updating 
>> loader?
>> 
>> My (limited) testing with VMs went without a hitch, but I want to make 
>> sure I don't paint myself into a corner.
> 
> Hi, I'm interested in this as well.
> 
> I'm not using root-on-zfs. The zpool is 5* spinning rust, the booting
> media is ssd/ufs2. Is updating the bootcode only relevant for
> root-on-zfs? I've not done that for a similarly configured desktop
> system, and it seems to be running stable/13 fine. (the desktop was a
> stable/12 to stable/13 upgrade).
> 
> thanks,

If you are not booting from zfs its seemless. Just remembe once you 
issue zpool upgrade you wont be able to go back to older version. If 
booting from ZFS, just update your boot loader.

I have updated a couple of systems from 12.2-RELEASE-p3 to 13.0-RC2. One 
using UEFI and the other using legacy bios with no problems.

for UEFI I mounted EFI Boot partition

EFI update, New ZFS data set was mounted at ROOT, zpool is mirror. 
Updated both EFI partitions in case primary goes offline.

zpool set bootfs=ssd/ROOT/13.0-RC2 ssd
mount -t msdosfs /dev/ada0p1 /mnt
cp ROOT/boot/loader.efi /mnt/EFI/BOOT/BOOTX64.efi
umount /mnt
mount -t msdosfs /dev/ada1p1 /mnt
cp ROOT/boot/loader.efi /mnt/EFI/BOOT/BOOTX64.efi
umount /mnt

Legacy Bios, again new ZFS data set was mounted at ROOT, and zpool is 
mirror, updated both boot partitions
zpool set bootfs=zroot/ROOT/13.0-RC2 zroot
gpart bootcode -b ROOT/boot/pmbr -p ROOT/boot/gptzfsboot -i 1 ada0
gpart bootcode -b ROOT/boot/pmbr -p ROOT/boot/gptzfsboot -i 1 ada1

Everything worked as expected.

-- 
Thanks,
    Dean E. Weimer
    http://www.dweimer.net/