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Date: Mon, 22 Jun 2009 15:29:58 +0200
From: Kevin Wolf <kwolf@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] block-raw: Make cache=off default again
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To: dlaor@redhat.com
Cc: qemu-devel@nongnu.org

Dor Laor schrieb:
> On 06/22/2009 04:08 PM, Anthony Liguori wrote:
>> Kevin Wolf wrote:
>>> Since the patch that suggested it woudl revert qcow2 to writeback 
>>> caching, in
>>> fact none of the drivers has had cache=off as default any more. This 
>>> patch
>>> restores the desired behaviour.
>> When has cache=off ever been the default?
>>
>> Moreover, why would we want to make it the default?  A patch with this 
>> drastic of a change really need a more 
> 
> It should be the default (or at least O_DSYNC) since plain users are not 
> aware that writeback might
> cause their image to get corrupted on host crash.

Anthony is right, I was confused. writeback isn't the default, it's
writethrough and it actually works. The code is just not explicit enough
when you're convinced that caching is meant be off by default because
this is what everyone is talking about.

Kevin