Re: grub-setup on ZFS (Re: [PATCH] Enable `grub-probe -t device' resolution on ZFS)

[Robert Millan]

2010/8/16, Seth Goldberg <address@hidden>:
>> Implicit approach only works for mirrored setup.  If you want to install
>> to all
>> members in a non-mirrored pool, you still need explicit approach, so I'd
>> only
>> implement implicit one if there's a clear benefit, such as the protection
>> offered by mirroring.  I would check if zfs.mod from grub-extras provides
>> this
>> protection before trying to answer this question.
>
>    That's true -- right now, we only support root on an n-way mirrored pool.
> If support is expanded in the future, why wouldn't a similar
> grub_util_raid_getmembers() not work in an analagous way to the mirrored
> case?

Sorry, it would work.  I just didn't think of this possibility because I find it
confusing.

In a mirrored setup, grub-setup does what user expects (copiing core.img
to each disk).  In a non-mirrored array, user could think grub-setup will do
the analogous (interleaving core.img), but this wouldn't work, so what
you propose is to do something different which would work but is probably
not what user expects.

Not that this matters a lot (in the end user can boot), but I can't see any
advantage in providing two ways to do the same thing, specially when it
isn't obvious they are equivalent.

Also, in ZFS there isn't a single device name that identifies the whole pool
(as with mdraid), which would make the semantics even more confusing.

-- 
Robert Millan