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1612 discussions

Buffered console with kvm ?
by Stephen Harris 16 Sep '12

16 Sep '12

My Centos 6 server acts as a KVM host for a number of guests. Each of these guests have been configured with a serial console so I can do things like virsh console test2 and get access to the console of that machine. However what would be really useful is if the console also had a "buffer" so that messages which appeared while I wasn't connected could still be seen (much in the way old-style serial-port terminal servers would buffer output). Is this possible, "natively" ? Otherwise I was thinking of doing something like running 'screen -d -m -S test2 virsh console test2' and then I can connect with "screen" But that doesn't feel as friendly. Any ideasor recommendations? -- rgds Stephen

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[Advice] CentOS6 + KVM + bonding + bridging
by SilverTip257 08 Sep '12

08 Sep '12

With the current talk on bonding, I have a few questions of my own. I'm setting up a KVM host with CentOS 6.3 x86_64 on which I'd like to attach the VMs to a bonded interface. My target setup is one where two GigE NICs are bonded and then the KVM bridge interface is attached to the bonded interface. Initially I tried to use the balance-alb mode (mode6), but had little luck (receiving traffic on the bond appeared to be non-functional from the perspective of a VM). After some reading [0] [1] - I switched the mode to balance-tlb (mode5) and hosts are now reachable. See bottom of [0] for a note on "known ARP problem for bridge on a bonded interface". I'd prefer mode5 or 6 since it would balance between my slave interfaces and need not worry about 802.3ad support (mode4) on the switch this host will be connected to. But the way it seems mode 6 isn't going to work out for me. (Maybe experimenting with mode4 is the way to go.) [0] http://www.linux-kvm.org/page/HOWTO_BONDING [1] https://lists.linux-foundation.org/pipermail/bridge/2007-April/005376.html My question to the members of this list is what bonding mode(s) are you using for a high availability setup? I welcome any advice/tips/gotchas on bridging to a bonded interface. Thanks! ---~~.~~--- Mike // SilverTip257 //

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802.3ad + Centos 6 + KVM (bridging)
by aurfalien 06 Sep '12

06 Sep '12

Hi all, Don't mean to double post as I sent this to the general Centos list. But, does any one have 802.3ad (mode 4) working on there Centos6 KVM setup? This would be a bridge+bond setup of course. If not possible, would I still bond the interfaces on the switch and then bond them in the guest rather then from within the hypervisor? - aurf

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Re: [CentOS-virt] wine
by Hossein Lanjanian 05 Sep '12

05 Sep '12

Thank you for your reply. Fortunatly, I can solve the problem after many trial and errors and googling. The following commabd line is help full: # setsebool -P wine_mmap_zero_ignore 1 On Sep 3, 2012 3:18 AM, "Mauricio" <raubvogel(a)gmail.com> wrote: > In other words, wine is a different program than virt. AFAIK it has its > own mailing list, but I would also try the centos.org forums. When you do > ask, make sure to include the relevant log files. Or at least a better > problem description > > Just blindly disabling selinux is not a good way to do things. > > > ------Original Message------ > From: Jan Harasym > Sender: centos-virt-bounces(a)centos.org > To: Discussion about the virtualization on CentOS > ReplyTo: Discussion about the virtualization on CentOS > Subject: Re: [CentOS-virt] wine > Sent: Sep 2, 2012 17:23 > > wine isn't virtualisation, you'll have trouble getting relevant support > here. > > On 1 Sep 2012, at 13:16, Hossein Lanjanian <hossein.lanjanian(a)gmail.com> > wrote: > > > Hi every body > > I have installed wine on the centos in my dual boot win7 & centos 6 > Vaio laptop system. every thing was OK. > > but after rebooting system, centos start loading but crash in the > loading step. > > > > I change selinux conf. with using CD Rescue option but it dosenot be > helpfull. > > please help > > > > > > > > -- > > With The Best > > H.Lanjanian > > _______________________________________________ > > CentOS-virt mailing list > > CentOS-virt(a)centos.org > > http://lists.centos.org/mailman/listinfo/centos-virt > > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org > http://lists.centos.org/mailman/listinfo/centos-virt > > > Sent via iPhone > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org > http://lists.centos.org/mailman/listinfo/centos-virt >

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wine
by Hossein Lanjanian 03 Sep '12

03 Sep '12

Hi every body I have installed wine on the centos in my dual boot win7 & centos 6 Vaio laptop system. every thing was OK. but after rebooting system, centos start loading but crash in the loading step. I change selinux conf. with using CD Rescue option but it dosenot be helpfull. please help -- With The Best H.Lanjanian

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Re: [CentOS-virt] wine
by Mauricio 02 Sep '12

02 Sep '12

In other words, wine is a different program than virt. AFAIK it has its own mailing list, but I would also try the centos.org forums. When you do ask, make sure to include the relevant log files. Or at least a better problem description Just blindly disabling selinux is not a good way to do things. ------Original Message------ From: Jan Harasym Sender: centos-virt-bounces(a)centos.org To: Discussion about the virtualization on CentOS ReplyTo: Discussion about the virtualization on CentOS Subject: Re: [CentOS-virt] wine Sent: Sep 2, 2012 17:23 wine isn't virtualisation, you'll have trouble getting relevant support here. On 1 Sep 2012, at 13:16, Hossein Lanjanian <hossein.lanjanian(a)gmail.com> wrote: > Hi every body > I have installed wine on the centos in my dual boot win7 & centos 6 Vaio laptop system. every thing was OK. > but after rebooting system, centos start loading but crash in the loading step. > > I change selinux conf. with using CD Rescue option but it dosenot be helpfull. > please help > > > > -- > With The Best > H.Lanjanian > _______________________________________________ > CentOS-virt mailing list > CentOS-virt(a)centos.org > http://lists.centos.org/mailman/listinfo/centos-virt _______________________________________________ CentOS-virt mailing list CentOS-virt(a)centos.org http://lists.centos.org/mailman/listinfo/centos-virt Sent via iPhone

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CentOS 6.2 / kvm / Windows XP sp3 guest crashes repeatedly after a few minutes
by Philip Bondi 27 Aug '12

27 Aug '12

Hello to all: Recently upgraded from CentOS 6.0 to 6.2 to get USB passthrough support by performing "yum update". USB passthrough works great, but now my Windows XP sp3 guest crashes repeatedly after a few minutes. [root@shackleton-eth0 log]# rpm -qa|egrep '(kvm|kernel|libvirt-|qemu)'|sort abrt-addon-kerneloops-2.0.4-14.el6.centos.x86_64 dracut-kernel-004-256.el6_2.1.noarch gpxe-roms-qemu-0.9.7-6.9.el6.noarch kernel-2.6.32-220.7.1.el6.x86_64 kernel-2.6.32-71.el6.x86_64 kernel-devel-2.6.32-220.7.1.el6.x86_64 kernel-devel-2.6.32-71.el6.x86_64 kernel-firmware-2.6.32-220.7.1.el6.noarch kernel-headers-2.6.32-220.7.1.el6.x86_64 libreport-plugin-kerneloops-2.0.5-20.el6.x86_64 libvirt-0.9.4-23.el6_2.6.x86_64 libvirt-client-0.9.4-23.el6_2.6.x86_64 libvirt-python-0.9.4-23.el6_2.6.x86_64 qemu-img-0.12.1.2-2.209.el6_2.4.x86_64 qemu-kvm-0.12.1.2-2.209.el6_2.4.x86_64 This message in /var/log/messages precedes every crash: [root@shackleton-eth0 log]# grep kvm /var/log/messages Mar 19 09:09:25 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 Mar 19 09:15:48 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 Mar 19 09:25:51 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 Mar 19 11:21:27 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 Mar 19 12:07:16 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 Mar 19 12:16:14 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 Mar 19 13:46:27 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 Mar 19 14:06:49 shackleton-eth0 kernel: kvm: 2889: cpu0 unhandled wrmsr: 0x198 data 0 CentOS 6.0 was stable. Windows XP sp3 did not crash. Formerly, I was running virtio-win-0.1-15.iso, but now upgraded to virtio-win-0.1-22.iso and Windows XP sp3 remains unstable.

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Accessing NTFS on host from XP/Win7 VM
by Rajagopal Swaminathan 22 Aug '12

22 Aug '12

Greetings, I have installed Centos 6.3 recently on bare metal (as dual boot with win 7) and want to access the existing NTFS through XP Guest. SELinux is enforcing and VM network is NAT. Google confused me more that educating me -- maybe I could not cobble up the right phrase. Any help appreciated. TIA It is my only system at home. -- Regards, Rajagopal

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KVM - Virtio drivers for Centos 5.1
by aurfalien 14 Aug '12

14 Aug '12

Hi all, Really enjoying KVM as I was a long time user of Xen. Both are cool, just enjoying the new thing. Wondering if any one could share some nuggets on how to get a Centos 5.1 VM guest to use virtio? Trying to use virtio over the ide. Thanks in advance, - aurf

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tuned-adm fixed Windows VM disk write performance on CentOS 6
by Julian price 12 Aug '12

12 Aug '12

On a 32bit Windows 2008 Server guest VM on a CentOS 5 host, iometer reported a disk write speed of 37MB/s The same VM on a CentOS 6 host reported 0.3MB/s. i.e. The VM was unusable. Write performance in a CentOS 6 VM was also much worse, but it was usable. (See http://lists.centos.org/pipermail/centos-virt/2012-August/002961.html) With iometer still running in the guest, I installed tuned on the CentOS 6 host and enabled the virtual-host profile. iometer showed the average disk write speed increasing immediately. A fresh iometer test reported a disk write speed of 80MB/s. I'm not sure if the tuned-adm virtual-host profile was available in 6.0 - it may be necessary to update to get it. http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Power_Man… Installation is quick & easy: yum install tuned tuned-adm profile virtual-host I'm surprised not to see any other posts on this subject. Maybe there's something peculiar about my setup that caused the dreadful write performance & tuned-adm happened to fix it. This problem has been a real headache and I'm extremely grateful to Philip Durbin and jimi_c for bringing the solution to my attention. The host server was rebuilt from scratch after a RAID1 simultaneous double disk failure (happily my DR strategy worked. Have you tested yours recently?). It appears that CentOS 6 has some different defaults (more conservative power saving?). Maybe upgrades don't change the defaults, so this issue only affects new CentOS 6 installs? The iometer settings were: 1000 sectors, 16 outstanding IOs, access specification: 16k, 0%read 0%random The figures I've reported above are the 'Total MBs per second' See http://www.iometer.org/doc/downloads.html In the process of researching the problem, 2 other quick & easy optimisations came to light, each adding a few more MB/s: - Set noatime. See: http://www.activoinc.com/blog/2009/08/25/setting-noatime-and-nodiratime-for… - Disable Windows disk cacheing: See http://pve.proxmox.com/wiki/Windows_2003_guest_best_practices On Windows 2008: Computer Mgmt -> Disk Mgmt -> Select Drive (system) -> properties -> Policies tab -> uncheck 'Optimize for quick removal'

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