Converting a non-HAST ZFS pool to a HAST pool

[Pete French]

> HAST metadata takes much more space than glabel metadata. The latter
> takes only one sector, while the former depends on provider size, but we
> have to keep entire extent bitmap there, so definitely more than one
> sector.

I am attempting to do the same thing - convert a ZFS pool over to using
hast. I have a current setup using gmirror, ggated and a pair of labeled
drives. Luckily it seems that the meta data used by gmirror+glabel is biiger
than that used by hast - so I should be able to do this without recreating
the pool.

I only mention it here because I know that the gmirror+ggate is a fairly
common setup. If you start with labeled drives then you will be able to
migrate to hast without any downtime.

-pete.