Re: [ovirt-users] Bad performance with Windows 2012 guests

Hi Vadim, I've tested the performance with CrystalDiskMark from inside the Windows guest. Using Win2k8 R2 I got expected values for my system, about 88 MB/s on 4k random with 32 queues and 500MB/s + sequential writes with 32 queues. Using a Windows 2012 VM on the same system it's only 33MB/s on 4k random with 32 queues and 300MB/s sequential writes. Similar tests with a linux VM show a bit better values than the Win2k8 R2 and respond ultra-fast. My hosts are connected via iSCSI using a 10 GbE link and a ZFS appliance as the storage system. All tests have been run several times with the same results.

Sven -----Ursprüngliche Nachricht----- Von: Vadim Rozenfeld [mailto:vrozenfe@redhat.com] Gesendet: Sonntag, 3. Mai 2015 14:35 An: Sven Achtelik Cc: Doron Fediuck; Martijn Grendelman; Karen Noel; users(a)ovirt.org Betreff: Re: AW: Bad performance with Windows 2012 guests On Sun, 2015-05-03 at 06:48 -0500, Sven Achtelik wrote: > Hi Doron, > > I've also noticed that there seems to be a difference in performance between Win2k8 R2/Linux and Windows Server 2012. After reading Martijns post I've done some speed test regarding the drive speeds and was looking for a way to compare the VMs on a more professional way. My tests showed, that on the same hardware, the Win2k8 R2 was faster in response and throughput on the disks. I found a utility that somehow measures the latency on a system and that also showed a significant difference. What is the correct way to do a performance test on a VM running in KVM ? > > Sven > Hi Sven, Can you specify the type of disk on your system - ide, virtio-blk, or virtio-scsi? We usually use iometer for disk performance profiling. Sequential read/write, block size from 4K up to 256K, queue depth from 1 to 64. Vadim. > -----Ursprüngliche Nachricht----- > Von: users-bounces(a)ovirt.org [mailto:users-bounces@ovirt.org] Im > Auftrag von Doron Fediuck > Gesendet: Samstag, 2. Mai 2015 10:50 > An: Martijn Grendelman > Cc: Karen Noel; users(a)ovirt.org; Vadim Rozenfeld > Betreff: Re: [ovirt-users] Bad performance with Windows 2012 guests > > > On Apr 30, 2015 14:03, Martijn Grendelman <martijn.grendelman(a)isaac.nl&gt; wrote: > > > > Hi, > > > > Ever since our first Windows Server 2012 deployment on oVirt (3.4 > > back then, now 3.5.1), I have noticed that working on these VMs via > > RDP or on the console via VNC is noticeably slower than on Windows > > 2008 guests on the same oVirt environment. > > > > Basic things like starting an application (even the Server Manager > > that get started automatically on login) take a very long time, > > sometimes minutes. Everything is just... slow. > > > > We have recently deployed Microsoft Exchange on a Windows Server > > 2012 guest on RHEV, and it doesn't perform well at all. > > > > I haven't been able to find the cause for this slowness; CPU usage > > is not excessive and it doesn't seem I/O related. Moreover, other > > types of guests (Linux and even Windows 2008) do not have this problem. > > > > We have 3 different environments: > > - oVirt 3.5.1, on old Dell servers with Penryn Family CPUs with > > fairly slow storage on replicated GlusterFS, running CentOS 6.6 > > - oVirt 3.5.1, on modern 6-core SandyBridge servers with local > > storage via NFS, running CentOS 7.0) > > - RHEV 3.4.4 on modern 10-core SandyBridge servers with an iSCSI SAN > > behind it, running on RHEV Hypervisor 6.5 > > > > All of these -very different- environments expose the same behaviour: > > Linux, Windows 2008 fast (or as fast as can be expected given the > > hardware), Windows 2012 painfully slow. > > > > All Windows 2012 servers use VirtIO disk and network. I think all > > drivers are from the virtio-win-0.1-74 ISO. > > > > Does anyone share this experience? > > Any idea why this could happen and how it can be fixed? > > Any other information I should share to get a better idea? > > > > Btw, for the guests on the RHEV environment, we have a case with > > RedHat support, but that doesn't seem to lead to a quick solution, > > hence I'm writing here, too. > > > > Thanks for any help. > > > > Regards, > > Martijn Grendelman > > Hi Martijn, > Can you please provide the QEMU command line, together with kvm and qemu version? > > This information will be helpful for reproducing the problem. However, if the problem is not reproducible on a local setup, we will probably need to ask collecting some performance information with xperf tool. > > Doron > _______________________________________________ > Users mailing list > Users(a)ovirt.org > http://lists.ovirt.org/mailman/listinfo/users >