FreeBSD-10.3 root ZFS redux

[Mel Pilgrim]

On 5/11/2016 11:20 AM, Graham Allan wrote:
> On 5/11/2016 1:13 PM, James B. Byrne wrote:
>>
>> I managed to get this reversed in my head as I composed.  The question
>> is what happens when a nominally 3TB HDD is put in that has fewer
>> accessible sectors than a similar 3TB drive already present?
>
> My understanding is that it would just be rejected (I see some older
> solaris examples mention a "device too small" error).
>
> Best practice is probably to create a gpt partition of some standard
> size on the drives before adding that to the pool, to give a little
> adjustment room, though I confess I have made all my pools to date using
> the raw drives (other than a geom label); and simply try to replace
> drives with the same model.

You need to do this anyway for root on ZFS without other storage in the 
system because of the freebsd-boot partition.