From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Daniel P. Berrange" Subject: Re: [Xen-devel] Re: Writing a tool for Shared Persistent Windows Boot Image Date: Thu, 28 Jun 2007 19:27:36 +0100 Message-ID: <20070628182736.GB12711@redhat.com> References: <2BB087BE-D323-4D8E-82F7-794C76ED2BCD@gmail.com> <467ABF50.50209@codemonkey.ws> <13A934B9-F615-4838-8D26-4E33F0BCFF2E@gmail.com> <467AE21F.1020700@codemonkey.ws> <37B43CC2-BED7-4336-9CC4-0CE1C7894458@gmail.com> <467AF0C6.5010101@codemonkey.ws> Reply-To: "Daniel P. Berrange" Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-users-bounces@lists.xensource.com Errors-To: xen-users-bounces@lists.xensource.com To: Jim Burnes Cc: xen-devel@lists.xensource.com, xen-users@lists.xensource.com, Anthony Liguori List-Id: xen-devel@lists.xenproject.org On Thu, Jun 28, 2007 at 12:18:47PM -0600, Jim Burnes wrote: > Anthony (and anyone else listening), > > I've installed Centos 5, Xen 3.1 (from the Xensource RPMs) and installed a > base Windows image to an LVM to test. > > The installation wen't fairly well and I resolved various issues like > getting the VMs to render to VNC displays properly. > > I even used LVM snapshotting to do some quick copy-on-write tests. In that > configuration I've had up to 7 Windows VMs running at the same time, on > separate IPs, writing to LVM copy-on-write snapshots. The only problem is > that LVM cow snapshots consume too much main memory. > > So I proceeded to my final test which was to replace the LVM storage with > QCOW storage and see how many Windows VMs I could run concurrently. (I'm > trying for 12). > > The only cow tool I had was qcow-create, so I downloaded the qemu RPMs and > installed them. > > I used img2qcow to convert my installed Windows LVM image to the qcow base > image. > I used qcow-img to create a copy-on-write snapshot of the base image. > I tried to boot with this as the new storage type by specifiying: > > disk = [ 'tap:qcow:/var/lib/xen/image/winflp.img,hda1,w', > 'file:/var/lib/xen/install/winflp.iso,hdc:cdrom,r'] > > (and other variations, by using 'hda' instead of 'hda1', using 'tap:aio' > instead of 'tap:qcow') > > But everytime I try to start the vm by 'xm create' it seems to create the VM > and the VM immediately exits, leaving hardly any trace of even booting. I > tried booting directly to hard drive C: and I tried booting to the CDROM. > Booting to the CDROM worked fine but reported no attached hard drive. > > The only thing I see is a trace in the xend.log file which indicates that > xend (or the VM) is attempting to generate some sort of hotplug event for > tap. Then the whole VM shuts down. > > Is there something I need to do before tap:qcow works? > > I suspect, but am having a hard time proving that either: > > (1) My version of Xen 3.1 doesn't support tap:qcow or It is not possible to use blktap with HVM guests - there was code which tried to make it work, but its utterly broken[1]. In my spare time I'm trying to fix it, but no ETA. Dan. [1] it is calling APIS in XenD which no longer exist & has a try..except block which silently catches & ignores the errors, so you never notice that it failed. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|