Re: [CentOS-virt] Pages In and Read Sectors in Guest Domain
On Sun, 6 Apr 2014, Deron wrote: Hello. I have been doing some performance tests with Xen and CentOS and have found some strange statistics when comparing the virtual memory (/proc/vmstat) and I/O (/proc/diskstat) statistics between the Domain 0 and guests. When I look at the pgpgin statistic it is exactly the same as the read sectors in Dom0. However, when I look at the same statistics in the guest, the read sectors is exactly 2x pgpgin. I have tried this on 2 different versions, each on a different physical server. Here is an example of the statistics over a 30 second period (while running a benchmark in Dom1) in the Dom0 and Guest Domain. pgpgin read sectors === = Dom0 1698024 1698024 Dom1 848412 1696824 I have looked at some various settings to see if I could explain it. I can't tell if the Dom1 guest kernel is reporting incorrectly, or there is some other explanation. If anyone has any ideas about this I would appreciate any feedback. Dom 0 kernels 3.10.29-11.el6.centos.alt.x86_64 3.4.54-8.el6.centos.alt.x86_64 Guest kernel 2.6.32-431.el6.x86_64 The numbers that you are seeing are probably wrong due to an accounting issue in blkfront or blkback. It would be interesting to know whether this happens even with the most recent kernels.___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
Re: [CentOS-virt] OpenVZ variant
Andres, thanks for your interest. Could you elaborate what your thoughts related to CentOS 7 and the CentOS virtualization SIG are? I am not sure I exactly understand what you are proposing and it is also not quite clear to me whether there is some overlap with other SIGs (such as the Cloud SIG). I guess the key question I have is whether you are suggesting / considering to use the output of the virtualization SIG as upstream for OpenNode and would want to contribute to the SIG. Best Regards Lars On 03/04/2014 21:30, Andres Toomsalu wrote: Dear Scott, Lars, Currently we already have CentOS 6 based respin (called OpenNode - http://opennodecloud.com) targeted for virtualization - supporting both OpenVZ and QEMU/KVM at the moment - yet it would be possible to add Xen/LXC/Docker support as well - as we are based on libvirt. We are just discussing some ideas how we would like to develop next major version - CentOS 7 based virtualization host - yet we would be really interested for having an open discussion and community based development - if anybody wants to join in or there will be some interest to create something like community CentOS virtualization host project - where we could join. Our current ideas are spinning around CoreOS like (perhaps stateless) CentOS 7 compute host with modern clustering built-in (perhaps etcd) - and we still want to continue to support both containers and full virtual machines on the same host. Hopefully also Docker will be mature enough soon and supporting OpenVZ userland tools - as LXC and OpenVZ share the kernel part and surprisingly LXC seems still not enough mature/feature rich - yet LXC project has existed already quite a long time (which makes me a bit pessimistic predicting on future LXC progress pace). LXC container isolation features still suck a bit (for production systems) and still no live migration feature - yet support for it seems to come from OpenVZ team - as http://criu.org. But hopefully we can get rid of OpenVZ patched kernels - so it will be only the choice of userspace tools (for containers). Our goal would be to have something way simpler than Openstack (which is huge and quite a mess in its current state - if you really want to create a production grade system with it) - and to have a nicely packaged + easy to use system (which might not support all 1001 ways of doing the same thing - yet enforcing some simple best-practices). So - if anybody interested - lets discuss! Kind regards, -- http://www.getpostbox.com-- Andres Toomsalu http://www.opennodecloud.com http://www.opennodecloud.com/ ___ CentOS-virt mailing list CentOS-virt@centos.org http://lists.centos.org/mailman/listinfo/centos-virt
