Date: Tue, 14 Apr 2009 20:50:58 +0200
From: Andi Kleen <andi@firstfloor.org>
To: Michael Tokarev <mjt@tls.msk.ru>
Cc: Andi Kleen <andi@firstfloor.org>, Mark Lord <lkml@rtr.ca>,
       Anton Ertl <anton@mips.complang.tuwien.ac.at>,
       linux-kernel@vger.kernel.org
Subject: Re: Out-of-order writing by disk drives
Message-ID: <20090414185058.GZ14687@one.firstfloor.org>
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On Tue, Apr 14, 2009 at 10:09:48PM +0400, Michael Tokarev wrote:
> Andi Kleen wrote:
> []
> >Where I see it as a problem is with virtualization; LVM seems to be the
> >most sane way to manage file systems for lots of VMs and you likely
> >want barriers there too.
> 
> Virtualisation is the best fit for partitionable raid1 arrays.
> It is, in fact, what we have here -- I tested LVM but rejected
> it because of this very issue - it does not support barriers.

It does now as of 2.6.29, as long as you only have a single
underlying device and use dm linear.

-Andi
> 

-- 
ak@linux.intel.com -- Speaking for myself only.
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