From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([208.118.235.92]:42556)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <stefanha@gmail.com>) id 1UUvEu-0001aM-NX
	for qemu-devel@nongnu.org; Wed, 24 Apr 2013 04:39:45 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <stefanha@gmail.com>) id 1UUvEt-0008Rr-Mj
	for qemu-devel@nongnu.org; Wed, 24 Apr 2013 04:39:44 -0400
Received: from mail-ee0-f45.google.com ([74.125.83.45]:34337)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <stefanha@gmail.com>) id 1UUvEt-0008Qe-Ge
	for qemu-devel@nongnu.org; Wed, 24 Apr 2013 04:39:43 -0400
Received: by mail-ee0-f45.google.com with SMTP id l10so605799eei.18
	for <qemu-devel@nongnu.org>; Wed, 24 Apr 2013 01:39:42 -0700 (PDT)
Date: Wed, 24 Apr 2013 10:39:40 +0200
From: Stefan Hajnoczi <stefanha@gmail.com>
Message-ID: <20130424083940.GC20971@stefanha-thinkpad.redhat.com>
References: <CACO=3k4VE80D0_AJW-MtPmkJpjLaCi3c8CHV+PJ1kJg_J=hsVQ@mail.gmail.com>
	<CAJSP0QXP3DeRBkjn526UwKwoB=xXGn4VJzfV=dXJ6BJLxN-E5w@mail.gmail.com>
	<CACO=3k68tJUfroz=XrjguFs0VXyCfAJzEuaX-9N5ZvB8X4U=1Q@mail.gmail.com>
	<CACO=3k7_nKTbvro3qcURDLxD1kQ+bWkGyHXE1kfbFtvpe2XWuA@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CACO=3k7_nKTbvro3qcURDLxD1kQ+bWkGyHXE1kfbFtvpe2XWuA@mail.gmail.com>
Subject: Re: [Qemu-devel] Adding Disk-Level Introspection to QEMU
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Wolfgang Richter <wolf@cs.cmu.edu>
Cc: qemu-devel <qemu-devel@nongnu.org>

On Tue, Apr 23, 2013 at 03:11:26PM -0400, Wolfgang Richter wrote:
> On Tue, Apr 23, 2013 at 2:31 PM, Wolfgang Richter <wolf@cs.cmu.edu> wrote:
> 
> > On Tue, Apr 23, 2013 at 2:21 PM, Stefan Hajnoczi <stefanha@gmail.com>wrote:
> >
> >> Eric's suggestion to use NBD makes sense to me.  The block-backup code
> >> can be extended fairly easier using sync mode=none (do not perform a
> >> background copy of the entire disk) and by disabling the bitmap
> >> (essentially "tap" mode).
> >
> >
> Also, as another thought, I think I can actually use the bitmap to implement
> an optimization.  In my code, I already use a bitmap to determine which
> sectors I want to introspect (ignoring portions of the disk greatly reduces
> required bandwidth and overhead; swap space for example isn't generally
> interesting unless you can interpret memory as well).   So I think I can
> adapt
> my code here as well.

Cool.  By the way, do you actually care about the data being written or
just which sectors were touched?

Stefan