Re: Out-of-order writing by disk drives

From: Andi Kleen
Date: Tue Apr 14 2009 - 14:48:37 EST


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@xxxxxxxxxxxxxxx -- Speaking for myself only.
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