Re: Linux ZFS Grub compatibility

[John Lane]

On 12/06/18 15:32, John Lane wrote:
> On 09/06/18 17:15, Xen wrote:
> 
>>
>> Grub on this system is Ubuntu default currently, so that means
>>
>> 2.02~beta2-36ubuntu11.3
>>
>> I don't know if there are any Ubuntu specific patches in there, I'd have
>> to check but.....
> 
> Thanks for that. It prompted me to spin up a Ubuntu 16.10 VM and, guess
> what? it works!
> 
> I used the exact same script to create my zpool and then tested in Grub,
> where the following worked flawlessly:
> 
> grub> search --set --label testpool
> grub> ls /ROOT/ubuntu@/boot
> 
> The expected files were listed, no errors or warnings. I did, however,
> have to "insmod part_gpt" but I did not need to "insmod zfs".
> 
> So it must be some issue with the Grub version on Arch. I would have
> expected that to be closer to vanilla than Ubuntu's but then maybe
> that's the problem. Like you said, I don't know if Ubuntu's grub
> contains any special ubuntu-specific patches.
> 
> Perhaps I should ask this over on the Arch ML ?
> 
> _______________________________________________
> Help-grub mailing list
> address@hidden
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> 

Further to this, I discover that the UBUNTU GRUB cannot read the zpool
created by Arch Linux but the ARCH GRUB can read the zpool created by
ubuntu.

Arch ZFS version is 0.7.9-1, ZFS pool version 5000, ZFS filesystem version 5
Ubuntu ZFS version is 0.6.5.8-0ubuntu1, ZFS pool version 5000, ZFS
filesystem version 5

Arch zpool features

address@hidden          enabled
address@hidden            active
address@hidden           active
address@hidden  disabled
address@hidden     active
address@hidden            active
address@hidden             active
address@hidden     enabled
address@hidden          active
address@hidden              enabled
address@hidden      disabled
address@hidden           enabled
address@hidden            disabled
address@hidden                 disabled
address@hidden                  disabled
address@hidden                  disabled
address@hidden     disabled

Ubuntu zpool features

address@hidden       enabled
address@hidden         active
address@hidden        active
address@hidden  active
address@hidden         active
address@hidden          active
address@hidden  enabled
address@hidden       active
address@hidden           enabled
address@hidden   disabled
address@hidden        enabled

Diff

address@hidden  disabled
address@hidden            disabled
address@hidden                 disabled
address@hidden                  disabled
address@hidden                  disabled
address@hidden     disabled

So the zpools are identical in terms of active/enabled features but a
zpool created by 0.7.9 gets those explicit disabled features whereas a
pool created by 0.6.5.8 does not. I assume it is this difference that is
confusing Grub.

I don't think this is necessarily a Grub or Arch or Ubuntu issue. I
think I ought to ask this to the ZOL people....