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1613 discussions

Windows Xen VM's have high guest CPU usage and poor performance
by Ryan Pugatch 26 Jan '10

26 Jan '10

Hello all, I have a PowerEdge 2950 that I am using to host Windows XP VM's under CentOS. I am experiencing poor performance in the Xen VM's. Any time I try to do something, the CPU usage (as reported by the Windows task manager) hits 100% for a few and then drops back down. This is causing the VM's to run sluggish and be quite annoying to use. Example.. I click IE.. cpu hits 100% and IE takes a bit to open. I go to a website.. 100%.. I click a link.. 100%. This is the case even if I only have one VM running. I now have 32 VM's running on the machine and dom0's cpu usage as reported by xm top is 622%. It seems like Xen is just performing poorly while handling these Windows VMs. Any suggestions? I have Windows VM's on other hardware (typically PowerEdge R905s and R710s and they seem ok). This 2950 is a decent machine.. 32G RAM, 2x Xeon E5405 (quad core) at 2ghz. And I'm only allocating 1 CPU and 768MB RAM for each VM. Sample config: name = "win01n" maxmem = 768 memory = 768 vcpus = 1 builder = "hvm" kernel = "/usr/lib/xen/boot/hvmloader" boot = "c" pae = 1 acpi = 1 apic = 0 localtime = 1 on_poweroff = "destroy" on_reboot = "restart" on_crash = "restart" device_model = "/usr/lib64/xen/bin/qemu-dm" usbdevice = "tablet" sdl = 0 vnc = 1 vncunused = 0 vncdisplay = "1" disk = [ 'file:/var/xen/running/win01n,ioemu:hda,w' ] vif = [ "bridge=xenbr0" ] serial = "pty" Thanks in advance for any insight! - Ryan

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Recent version of open-vm-tools SRPM??
by David Knierim 22 Jan '10

22 Jan '10

I want to create some rpms to install the open-vm-tools on my CentOS 5.4 servers. I have not been able to find any srpms that are of recent vintage (The most recent I have found uses the version of open-vm-tools released in Dec. 2008). Before I spend a lot of time building a new srpm, I thought I would ask if anyone has already done this... Thanks, David

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VirtIO with CentOS 5.4
by Bill McGonigle 22 Jan '10

22 Jan '10

Hi, all, I'm attempting to run a Windows 2003 (32-bit) VM under CentOS 5.4, generally following: http://wiki.centos.org/HowTos/KVM I've seen nice performance benefits with the VirtIO driver under Fedora, so I'd like to get that running with CentOS as well. I have the September drivers build .iso. According to: http://www.linux-kvm.org/page/Virtio I need a KVM version 60 or later - fair enough. Back at the wiki there's a note about later KVM in -testing, and sure enough there's a -66 there, but it's only built for an old kernel. I got that SRPM and tried to build it against the current kernel, but get kmod build errors, ala: /root/rpmbuild/BUILD/kvm-kmod-66/_kmod_build_/kernel/external-module-compat.h:421: error: redefinition of typedef 'bool' ... /root/rpmbuild/BUILD/kvm-kmod-66/_kmod_build_/kernel/external-module-compat.h:734:1: warning: "__aligned" redefined The wiki also has a note about -84 being in Levente Farkas's repo, but those don't appear to be there any longer. So, questions: 1) what are folks generally using for VirtIO-capable KVM on CentOS 5.4? 2) given that the upstream has Windows drivers available, I'm curios how they're handling the issue, and if we're in sync. 3) does anybody have the SRPM that was at Farkas's repo or know if it went elsewhere? I assume the build issues have been solved there already. I'd be happy to update the Wiki with info from responses here. Thanks, -Bill -- Bill McGonigle, Owner BFC Computing, LLC http://bfccomputing.com/ Telephone: +1.603.448.4440 Email, IM, VOIP: bill(a)bfccomputing.com VCard: http://bfccomputing.com/vcard/bill.vcf Social networks: bill_mcgonigle/bill.mcgonigle

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boot order with Xen domxml
by Mr. X 19 Jan '10

19 Jan '10

Hey Virtualeers, When using domxml to configure a Xen domain, where is the meta spec for boot order? Before domxml, using xen-xm, this was easy: boot = 'dca' ; 1-CD | 2-HD | 3-floppy When I try adding this below with Virsh (vi), it is erased in Xen domains <boot dev='hd'> In KVM domains it is accepted. -- Mark

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Xen Database vms
by Ben M. 15 Jan '10

15 Jan '10

Are "centralized" database (SQL) servers best left out of virtualization and committed to their own hardware like the "old days" or are there some guidelines one should consider in setting them up? I'm not talking mega-large recordsets, but large enough to handle multiple years of CRMs and intensive querying, Accounting Systems and so forth. Fundamental website CMS database is a no-sweat issue. This would be on plain vanilla CentOS/Xen stock. All usual SQL server flavors considered. I'm trying to get an idea of where I am ultimately heading in my LANs.

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KVM management tools.....
by Tom Bishop 12 Jan '10

12 Jan '10

Looking at what my best options for managing KVM via a gui. Running Centos 5.4 and have several machines and want to migrate off of vmware server 2.x. So far it appears that the management tools haven't quite cought up to Vmware but are gaining and closing. I have been looking at convirt, and others. I like what I see in Ovirt but I'm not sure it is available for centos 5.4, or is it? Is there anyone running ovirt in centos? Also, what are folks using for their management tools for KVM, Thanks.....

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Help with the bugtracker
by Karanbir Singh 12 Jan '10

12 Jan '10

Hi Guys, There are a fair few issues reported at bugs.centos.org around virt issues, Xen / KVM and even VMware stuff. And I know there is a lot of knowledge and talent around those areas here on this list. Just wondering if some of the people here might be able to help with those issues on bugs.c.o - it should not be more than a few hours / week in terms of commitment. Thanks for considering. -- Karanbir Singh London, UK | http://www.karan.org/ | twitter.com/kbsingh ICQ: 2522219 | Yahoo IM: z00dax | Gtalk: z00dax GnuPG Key : http://www.karan.org/publickey.asc

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KVM Guest not using MAC address specified in XML file
by Neil Aggarwal 11 Jan '10

11 Jan '10

Hello: I have a server running Centos 5.4 with KVM. When I specify a MAC address in a guest's XML file: <interface type='bridge'> <mac address='00:00:00:00:10:67'/> <source bridge='br0'/> <target dev='v1067'/> </interface> I get a different answer from ifconfig: v1067 Link encap:Ethernet HWaddr D2:7A:F7:E5:09:B0 Any ideas why the address is different? Thanks, Neil -- Neil Aggarwal, (281)846-8957, http://UnmeteredVPS.net CentOS 5.4 VPS with unmetered bandwidth only $25/month! No overage charges, 7 day free trial, PayPal, Google Checkout

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QEMU/KVM: SELinux denial on /dev/zero when starting a VM
by Mathieu Baudier 08 Jan '10

08 Jan '10

Hi, on an up to date CentOS 5.4 x86_64 (test machine), I systematically get the following SELinux denial when I start a QEMU/KVM virtual machine via virt-manager: SELinux is preventing qemu-kvm (qemu_t) "execute" to /dev/zero (zero_device_t). (full alert below) Running the command suggested by the alert (restorecon -v '/dev/zero') does not solve the problem. This does not prevent the VM to run, but I would like to better understand what is happening here and the potential impact on performance. And if there is not impact, find a way to get rid of this warning... Thanks in advance for any idea! Mathieu Summary: SELinux is preventing qemu-kvm (qemu_t) "execute" to /dev/zero (zero_device_t). Detailed Description: SELinux denied access requested by qemu-kvm. It is not expected that this access is required by qemu-kvm and this access may signal an intrusion attempt. It is also possible that the specific version or configuration of the application is causing it to require additional access. Allowing Access: Sometimes labeling problems can cause SELinux denials. You could try to restore the default system file context for /dev/zero, restorecon -v '/dev/zero' If this does not work, there is currently no automatic way to allow this access. Instead, you can generate a local policy module to allow this access - see FAQ (http://fedora.redhat.com/docs/selinux-faq-fc5/#id2961385) Or you can disable SELinux protection altogether. Disabling SELinux protection is not recommended. Please file a bug report (http://bugzilla.redhat.com/bugzilla/enter_bug.cgi) against this package. Additional Information: Source Context system_u:system_r:qemu_t:SystemLow-SystemHigh Target Context system_u:object_r:zero_device_t Target Objects /dev/zero [ chr_file ] Source qemu-kvm Source Path /usr/libexec/qemu-kvm Port <Unknown> Host alma Source RPM Packages kvm-83-105.el5_4.13 Target RPM Packages Policy RPM selinux-policy-2.4.6-255.el5_4.1 Selinux Enabled True Policy Type targeted MLS Enabled True Enforcing Mode Enforcing Plugin Name catchall_file Host Name alma Platform Linux alma 2.6.18-164.9.1.el5 #1 SMP Tue Dec 15 20:57:57 EST 2009 x86_64 x86_64 Alert Count 10 First Seen Tue 05 Jan 2010 05:12:20 AM CET Last Seen Tue 05 Jan 2010 05:22:03 AM CET Local ID 8fb024fb-aa09-4177-84d7-55e5156e9538 Line Numbers Raw Audit Messages host=alma type=AVC msg=audit(1262665323.833:106): avc: denied { execute } for pid=8901 comm="qemu-kvm" path="/dev/zero" dev=tmpfs ino=2421 scontext=system_u:system_r:qemu_t:s0-s0:c0.c1023 tcontext=system_u:object_r:zero_device_t:s0 tclass=chr_file host=alma type=SYSCALL msg=audit(1262665323.833:106): arch=c000003e syscall=9 success=no exit=-13 a0=0 a1=2000 a2=7 a3=2 items=0 ppid=1 pid=8901 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=(none) ses=4294967295 comm="qemu-kvm" exe="/usr/libexec/qemu-kvm" subj=system_u:system_r:qemu_t:s0-s0:c0.c1023 key=(null)

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Re: [CentOS-virt] Xen box down
by Christopher G. Stach II 07 Jan '10

07 Jan '10

----- "Ben M." <centos(a)rivint.com> wrote: > Error is: "duplicate or bad block in use" It's probably just that fsck can't automatically fix some dirtiness and not a big deal. If you aren't prompted for a password or to log in to fix manually, get to the grub menu, edit the grub command line, stick ``single'' and/or ``init=/bin/sh'' on the end, boot, and run fsck manually. If you just want the machine up in a possibly slightly fucked state, just answer "yes" to everything. If not and you care a little bit about maybe getting some data back, see the next paragraph. (It's usually not that bad unless you have a skilled enemy or very bad luck.) You can probably have someone do all of it over the phone. If it doesn't even get that far or fsck can't fix it automatically, you're probably screwed. Whenever that has happened to me, I just do a block level dump of the partition/disk and recover from that image. It's a lot easier. Anyway, it is probably fine. If it isn't, you can always try pulling each of the disks or setting it back to use a single disk to try and isolate the problem. Also, switch to MD RAID. :) -- Christopher G. Stach II http://ldsys.net/~cgs/

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