From owner-freebsd-geom@FreeBSD.ORG  Wed Jul  8 08:38:05 2009
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To: bp@barryp.org, dan.naumov@gmail.com
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From: Pete French <petefrench@ticketswitch.com>
Date: Wed, 08 Jul 2009 09:38:01 +0100
Cc: freebsd-stable@freebsd.org, freebsd-geom@freebsd.org
Subject: Re: glabel metadata protection (WAS: ZFS: drive replacement
	performance)
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> I would say in this case you're *not* giving the entire disk to the 
> pool, you're giving ZFS a geom that's one sector smaller than the disk. 
>   ZFS never sees or can touch the glabel metadata.

Is ZFS happy if the size of it's disc changes underneath it ? I have
expanded a zpool a couple of times simply by changing the size of
the partition and rebooting the machine - it comes up with the new
amount of free space fine. Never tried it the other way though. The
reason I mention it is that someone suggested glabeling a drive in
an existing pool and using replace to swap it over. Which should be good
I guess unless the last sector was in use. ZFS spreads stuff all over the
disc as I unserdtand it though, so that might not be a good assumption,
even on a fairly empty filesystem.

-pete.