From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Yang, Xiaowei" <xiaowei.yang@intel.com>
Subject: Stubdom and blktap
Date: Sun, 28 Sep 2008 15:40:57 +0800
Message-ID: <48DF3509.8010003@intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xensource.com>
List-Unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: xen-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org

Recently we had a try of stubdom, whose general status is good.

One issue we found is with aio/sync blktap as backend, disk performance 
is obviously slower, and there are some IDE kernel error messages (like 
irq timeout) at boot time.

Another issue (not stubdom specific) comes from blktap's support for 
QCOW image which is based on a backing file. We never tried this 
configure before. The root cause is that in tdqcow_get_parent_id(), the 
backing file is hard-coded to be QCOW type and tdqcow_validate_parent() 
also presumes it, though the backing file is a raw image normally. With 
the image type set correctly and a good method for image validation, 
QCOW works.

Thanks,
Xiaowei