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From: Paul Brook <paul@codesourcery.com>
Subject: Re: [Qemu-devel] [RFC] Disk integrity in QEMU
Date: Fri, 10 Oct 2008 13:59:58 +0100
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To: qemu-devel@nongnu.org
Cc: Chris Wright <chrisw@redhat.com>, Mark McLoughlin <markmc@redhat.com>, kvm-devel <kvm-devel@lists.sourceforge.net>, Laurent Vivier <Laurent.Vivier@bull.net>, Ryan Harper <ryanh@us.ibm.com>, Avi Kivity <avi@redhat.com>

>> - OS development tool
>> - casual or client-side virtualization
>> - server partitioning

> > Absoutely agree that the default should be safe. I don't have enough 
> > knowledge to say whether O_DIRECT/O_DSYNC is best - which also implies
> > we should choose the best setting by default, because we can't expect
> > users to know the tradeoffs either.
>
> The fact that there are different use models for qemu implies that the
> default must be chosen at some higher level than qemu code itself.  It
> might be done using /etc/qemu or ~/.qemu, or at the management
> interface, but there is no best setting for qemu itself.

This suggests that the most appropriate defaults are for the users that are 
least likely to be using a management tool.  I'd guess that the server 
partitioning folks are most likely to be using a management tool, so qemu 
defaults should be setup for casual/development use. I don't have hard data 
to back this up though.

Paul