[rescue] expanding a ZFS pool: leave slack space?

[Joshua Oakes]

I feel like you should be able to just delegate the whole drive to the
pool. Add it as a third disk in the mirror if you have the physical space.
The mirror will accept it, there should be a zfs option enable_expand, that
is defaulted to enabled. The mirror operates on smallest drive size, when
they are all replaced they will automagically grow. Easiest method to grow
your pool size. No hand partitioning, just replace one mirror disk at a
time and let it resilver, rinse repeat.

On Fri, Apr 30, 2021, 10:42 AM Scott Newell <newell+rescue at n5tnl.com> wrote:

> I've got a 1 TB ZFS pool (2 drive mirror) that I'm going to expand to
> 4 TB. Currently the 1 TB drives have partition tables, with the
> partitions and pool a few hundred MB less than the total drive capacity.
>
> When installing the new drives, should I again partition them so the
> pool ends up a bit smaller than the entire drive? If so, what's the
> rule of thumb? 0.1% of the drive? 512 MB? 8 GB?
>
> My concern is that in the future a replacement drive might not be
> exactly the same number of sectors, and if it's too small, the mirror
> obviously won't accept it.
>
> thanks!
>
> --
> newell  N5TNL
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