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Date: Mon, 3 Jun 2013 01:46:55 +0400 (MSK)
From: Dmitry Morozovsky <marck@rinet.ru>
To: Warren Block <wblock@wonkity.com>
Subject: Re: Corrupt GPT header on disk from twa array - fixable?
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On Sun, 2 Jun 2013, Warren Block wrote:

> > > gmirror is good.  GPT is also good.  The combination is a problem. gmirror
> > > metadata overwrites the backup GPT, so those disks will show "corrupt"
> > > also.
> > > For now, the recommended workaround is to just use MBR, which doesn't have
> > > any
> > > metadata at the end of the disk.
> > 
> > ... or gmirror not whole disks, but GPT partitions (as OP does, as far as I
> > can
> > tell from gmirror dmesg reports)
> 
> That works, but if there is more than one partition per disk, rebuilds fight
> with each other for the heads.

Right; OTOH, there is usually no more than one or two partitions which are 
under write pressure, so *usually* you'll find rebuilding, say, /dev/mirror/var 
and /dev/mirror/db (at least most of our gmirror-setup servers show that)

On the third hand, if you have enough memory, ZFS is both simplier and more 
lazy regarding repairs ;)

-- 
Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
[ FreeBSD committer:                                 marck@FreeBSD.org ]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru ***
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