From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: Which disk backend to use in domU?
Date: Mon, 14 Jun 2010 11:49:45 +0100
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To: Neobiker <neo-ml-efw-1106@neobiker.de>
Cc: xen-devel@lists.xensource.com, Daniel Stodden <daniel.stodden@citrix.com>
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On 06/11/2010 07:11 PM, Neobiker wrote:
> Hi
>
> Valtteri Kiviniemi-2 wrote:
>   
>> Hi, Ah, misunderstanding sorry, you were talking about disk images :)
>>
>>     
> I'm talking about this config:
> disk        = [
>                   'phy:/dev/vm/vm01,xvda1,w',
>                   'phy:/dev/vm/vm01-swap,xvda2,w',
>                   'phy:/dev/daten/devel_debian_amd64,xvda3,w',
>               ]
>   

file: is definitely unsafe; its IO gets buffered in the dom0 pagecache,
which means the guests writes aren't really writes.  I believe phy: has
similar problems, whereas tap:aio: implemented direct IO.  But someone
more storagey can confirm.

    J