Re: [CentOS-virt] Performance tunning CentOS / Xen
On Sun, Aug 23, 2009 at 01:34:08PM +0800, Ryan Chan wrote: Hello, I have followed standard documents to install CentOS 5.3 Xen. After playing around, stuffs are OK. So I move forward to tune the performance, are there any recommended documents/tutorial that specialized on performance tuning VM host/guest, on CentOS / Xen architecture? I usually limit dom0 memory to 512 MB or 1024 MB to make sure memory ballooning is not needed while creating new domUs/guests. It could cause weird problems if you boot up your dom0 with all the physical memory available to it (possibly multiple gigabytes), and later it gets ballooned down to only a few hundred MBs. Also you might want to dedicate a cpu core only for dom0, so disk/network IO requests from domUs will always have enough CPU power to be executed by dom0. Xen hypervisor (xen.gz) boot options to play with: - dom0_max_vcpus= - dom0_vcpus_pin - dom0_mem= And possibly running xm vcpu-pin commands after startup to force dom0 vcpu(s) to a specific physical cpu(s)/core(s). In addition to that you also need to limit the physical cpus the domUs/guests can use (so the dom0 cpus/cores stay reserved only for dom0). Also you might want to give dom0 more weight than domUs so it is always able to have enough cpu time. References: http://article.gmane.org/gmane.comp.emulators.xen.user/45042 http://lists.xensource.com/archives/html/xen-devel/2009-07/msg00875.html http://lists.xensource.com/archives/html/xen-devel/2009-07/msg00873.html -- Pasi ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] virtio
On Sat, 2009-08-22 at 11:36 -0400, Kanwar Ranbir Sandhu wrote: I've tried change an existing VM to virtio for disk and network, but each time I start it, I get this error: error: Failed to start domain popdns02 error: internal error unsupported disk type 'vda' I don't know why this is happening. From what I've read, virtio should be available. Can someone please tell me what I'm doing wrong? Anyone? I'd really like to fix this. Regards, Ranbir -- Kanwar Ranbir Sandhu Linux 2.6.27.29-170.2.78.fc10.x86_64 x86_64 GNU/Linux 20:46:00 up 7 days, 21:42, 4 users, load average: 0.09, 0.06, 0.03 ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
