Hi,Thanks for the hints , I did experiment with the changes you suggested and now we were able to achieve the following result : the performance of the domU is 50 % of the dom0 .
Is it possible to improve these numbers more ?Also , do you have any advice on where to find extensive documentation on how to use Xen ?
Thank you Luca Il 05/01/2016 15:05, Stefano Stabellini ha scritto:
There are a few issues in the config files. In conf_DomU_WindowsHVM: - device_model is set to /usr/lib64/xen/bin/qemu-dm, which is the old qemu-xen-traditional device model, known to have worse disk performance. Just delete this line to use the newer QEMU based tree. - disk is set to [ '/dev/vg0/winvirtio,raw,xvda1,rw' ], but you cannot expose only a partition of a disk to a Windows HVM domain. The correct disk line would be: disk = [ '/dev/vg0/winvirtio,raw,hda,rw' ] In conf_DomU_Xen: - you are missing builder="hvm", which means you are using a PV guest rather than an HVM guest. PV guests tends to be slower on new hardware. What version of Xen are you using? On Tue, 5 Jan 2016, Luca Tongiani wrote:Sorry but I sent these logs because I have no longer available the Virtualizer of Windows DomU . In any case the problem of the performance of disks is present both in the case of Linux machines PV and Windows machines HVM . I attach the complete log of the server and the conf of my HVM Windows Machine. Thanks again Il 05/01/2016 13:42, Stefano Stabellini ha scritto: The xenstore-ls output is not complete. Could you please send it again? I noticed from the DomU config file that it is not a Windows VM, as previously discussed, but a Linux VM. That is OK, but of course in that case you won't be able to use the Windows PV drivers which I linked. Linux has its own set of drivers. Did you enable the Xen PV frontends in the Linux kernel you use (/var/xen/boot/vmlinuz-4.0.5-gentoo_bmsbackup)? Did you compile them a built-in or as modules? On Tue, 5 Jan 2016, Luca Tongiani wrote: Hi, thanks in advance for your reply :) I have attached the following email configuration DomU and the output you have requested . Performance disk are all my machines the most serious problem , even if they are used powerful hardware . Differences in Disk writing in DomU are 1/3 of those of the Dom0 . Thank you in advance Luca Il 05/01/2016 12:09, Stefano Stabellini ha scritto: Could you please post your VM config file and the output of xenstore-ls once the VM has completed the boot sequence? On Tue, 5 Jan 2016, Luca Tongiani wrote: Hi Stefano, im writing to you because im having issue with I/O disk in my DomU With Xen (Gentoo based system). I tried to use the driver that you provided for the PV . But the results are still not good , there is no way to support the use of Xen VirtIO disk ? Many thanks in advance Luca Il 12/16/15 12:31, Stefano Stabellini ha scritto: Hello Luca, the recommended way to increase disk performance would be to use Xen PV disks. You just need to install the Windows PV drivers: http://www.xenproject.org/developers/teams/windows-pv-drivers.html But using VirtIO disk should also increase performance, even though most probably not as much. Cheers, Stefano On Tue, 15 Dec 2015, Luca Tongiani wrote: Hi to all, I'm writing you this mail for asking some advice about a great problem i'm havin in running a Windows VM (HVM) onto a Xen (Gentoo based) Hypevisor. I need to achieve maximum performance from this VM because of intense SQL tasks running in it. I've seen good improvement in IO on disk using VirtIO on a Windows VM onto a QEMU (QNAP) hypervisor, and i'm tryin to use this feature also on my Xen HV. Is VirtIO disk a good way to improve performance? Thx in advance and hope to keep in touch -- Luca Tongiani Sinte srl Soluzioni Informatiche e Telematiche via Monte Grappa 4/B 20900 Monza (MB) Cel (+39) 339 745 49 21 Tel (+39) 039 200 59 60 Fax (+39) 039 200 69 42 Web www.sinte.net -- Luca Tongiani Sinte srl Soluzioni Informatiche e Telematiche via Monte Grappa 4/B 20900 Monza (MB) Tel (+39) 039 200 59 60 Fax (+39) 039 200 69 42 Web www.sinte.net -- Luca Tongiani Sinte srl Soluzioni Informatiche e Telematiche via Monte Grappa 4/B 20900 Monza (MB) Tel (+39) 039 200 59 60 Fax (+39) 039 200 69 42 Web www.sinte.net -- Luca Tongiani Sinte srl Soluzioni Informatiche e Telematiche via Monte Grappa 4/B 20900 Monza (MB) Tel (+39) 039 200 59 60 Fax (+39) 039 200 69 42 Web www.sinte.net
-- *Luca Tongiani* *Sinte* srl Soluzioni Informatiche e Telematiche via Monte Grappa 4/B 20900 Monza (MB) *Tel* (+39) 039 200 59 60 *Fax* (+39) 039 200 69 42 *Web* www.sinte.net <http://www.sinte.net/>
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