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Date: Wed, 31 Oct 2012 15:40:48 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] On block interface types in general,
	IF_AHCI in particular
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To: Markus Armbruster <armbru@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Jason Baron <jbaron@redhat.com>, qemu-devel@nongnu.org, Alexander Graf <agraf@suse.de>, Gerd Hoffmann <kraxel@redhat.com>, Anthony Liguori <anthony@codemonkey.ws>

Il 31/10/2012 15:20, Markus Armbruster ha scritto:
> One more thing: on a *major* upgrade, I'd rather deal with immediately
> obvious breakage (does not boot) than rotten performance.
> 
> If we make "q35 with compat IDE" the default, we'll have to tell users
> many, many times not to use the default :(

Well, compat IDE is not on the same league as writethrough for bad
performance, and virtio is anyway the better choice (and not available
just with a different machine type).

If they complain we should send them to virtio just as likely.  And
perhaps we should send them straight to libvirt and libosinfo.  Because
in some time we'll probably have the same problem with virtio-scsi vs.
virtio-blk (features vs. performance), and externalizing the decision is
the only sane thing to do.

Paolo