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Date: Sun, 12 Oct 2008 13:00:48 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [RFC] Disk integrity in QEMU
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To: qemu-devel@nongnu.org
Cc: Chris Wright <chrisw@redhat.com>, Mark McLoughlin <markmc@redhat.com>, Ryan Harper <ryanh@us.ibm.com>, kvm-devel <kvm@vger.kernel.org>, Laurent Vivier <Laurent.Vivier@bull.net>

Jamie Lokier wrote:
> Dor Laor wrote:
>   
>> Actually this is what happens on mainline qemu with cache=off.
>>     
>
> Have I understood right that cache=off on a qcow2 image only uses
> O_DIRECT for the leaf image, and the chain of base images don't use
> O_DIRECT?
>   

Yeah, that's a bug IMHO and in my patch to add O_DSYNC, I fix that.  I 
think an argument for O_DIRECT in a leaf and wb in the leaf is seriously 
flawed...

Regards,

Anthony Liguori

> Sometimes on a memory constrained host, where the (collective) guest
> memory is nearly as big as the host memory, I'm not sure this is what
> I want.
>
> -- Jamie
>
>
>