Sebastien, Thanks for your response. So there is no better way, it seems.
On Fri, Jun 12, 2015 at 3:06 PM, Sebastien Han <[email protected]> wrote: > Unfortunately crucial flags like ‘iothreads’ and ‘io’ don’t exist in Nova. > They are also part of the simple patches that take ages (and eventually get > abandoned) to be merged. > I don’t think editing all of your instance is a good way to do it either. > > If you want to hack an instance, you should probably edit all xml files on > your system and simply restart the VM using virsh itself. > As far as I remember there is on file in /var/lib/nova/instances/<id> and one > somewhere in /etc/libvirt > > >> On 12 Jun 2015, at 08:49, pushpesh sharma <[email protected]> wrote: >> >> Hi list, >> >> I need some expert opinion on some problem I am facing with >> OpenStack+Ceph environment. >> >> I running a 3+ node cluster with OpenStack Juno. It is using ceph RBDs >> as cinder volumes. Functionally setup is working fine. However my >> expectation are related to block performance of RBDs inside a VM. >> >> I am observing a throttling effect in 100%- 4K RR iops after a point. >> Lots of CPU >> cycles got wasted in iowait. I suspect a single iothread per VM is >> causing this.I came to know about few tuning parameter that libvirt >> provides. It looks pretty straight forward to set these parameter >> in domain xml . However I am not able to do so. I didn't find any way >> to pass these >> parameter form nova directly, and when I edit domain.xml directly >> using 'virsh edit' the changes vanish even after saving the xml >> properly.(I know it is not a clean way to this, but a hack) >> >> It could be validation problem:- >> >> ############ >> #virsh dumpxml instance-000000c5 > vm.xml >> #virt-xml-validate vm.xml >> Relax-NG validity error : Extra element cpu in interleave >> vm.xml:1: element domain: Relax-NG validity error : Element domain >> failed to validate content >> vm.xml fails to validate >> ################## >> >> Second approach I took was to setting QoS in volumes types. But there >> is no option to set iothreads per volume, there are parameters related >> to max_read/wrirte ops/bytes. >> >> Thirdly, editing Nova flavor and proving extra specs like >> hw:cpu_socket/thread/core, can change guest CPU topology however again >> no way to set iothread. It does accept hw_disk_iothreads(no type check >> in place, i believe ), but can not pass the same in domain.xml. >> >> Please suggest me a way to set the same. >> >> -- >> -Pushpesh >> >> _______________________________________________ >> OpenStack-operators mailing list >> [email protected] >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators > > > Cheers. > –––– > Sébastien Han > Senior Cloud Architect > > "Always give 100%. Unless you're giving blood." > > Mail: [email protected] > Address: 11 bis, rue Roquépine - 75008 Paris > -- -Pushpesh _______________________________________________ OpenStack-operators mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
