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From: Jens Axboe <jens.axboe@oracle.com>
To: Chris Mason <chris.mason@oracle.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	Michael Tokarev <mjt@tls.msk.ru>, Mark Lord <lkml@rtr.ca>,
	Anton Ertl <anton@mips.complang.tuwien.ac.at>,
	linux-kernel@vger.kernel.org, agk@redhat.com
Subject: Re: Out-of-order writing by disk drives
Date: Wed, 15 Apr 2009 14:46:01 +0200	[thread overview]
Message-ID: <20090415124601.GM5178@kernel.dk> (raw)
In-Reply-To: <1239737226.28321.22.camel@think.oraclecorp.com>

On Tue, Apr 14 2009, Chris Mason wrote:
> On Tue, 2009-04-14 at 20:50 +0200, Andi Kleen wrote:
> > 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.
> 
> Eric Sandeen noticed this is actually still broken:
> 
> http://lkml.org/lkml/2009/3/23/360

Alasdair promised to push the remaining barrier bits for 2.6.30, so
hopefully it should all be in working order Real Soon Now.

-- 
Jens Axboe


  reply	other threads:[~2009-04-15 12:46 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-07 20:04 Out-of-order writing by disk drives Anton Ertl
2009-04-14 14:10 ` Andi Kleen
2009-04-14 16:33   ` Anton Ertl
2009-04-14 17:24     ` Andi Kleen
2009-04-14 17:40       ` Mark Lord
2009-04-14 17:48         ` Michael Tokarev
2009-04-14 17:54         ` Andi Kleen
2009-04-14 18:09           ` Michael Tokarev
2009-04-14 18:50             ` Andi Kleen
2009-04-14 19:27               ` Chris Mason
2009-04-15 12:46                 ` Jens Axboe [this message]
2009-04-17 19:46         ` Folkert van Heusden
2009-04-17 20:29           ` Andi Kleen
2009-04-17 21:07 ` Folkert van Heusden
2009-04-18  9:06   ` Anton Ertl

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