On Fri, Sep 26, 2014 at 01:03:06PM -0400, Sean Toner wrote: > On Friday, September 26, 2014 03:09:05 PM Daniel P. Berrange wrote: > > > > 1. What happens on an overcommit for the number of guest CPUs? > > > > > > - For example, if I have a system with 2 sockets 4 cores each, > > > what > > > > > > would happen if I have 2 guests, each one wanting 6 cores (assuming > > > this is not in violation of the hw:cpu_max_cores)? > > > 2. What happens on an overcommit on memory? > > > > The memory and CPU overcommit settings are still honoured when Nova > > does NUMA placement. eg if you have a host with 2 NUMA nodes, each > > with 4 physical CPUs and CPU overcommit ratio of x3, then Nova will > > treat this as being a system with 2 NUMA nodes, each with 12 CPUs. > > Similarly for memory overcommit. > > > > So in the scenario you describe above, each guest configuration would be > constrained to one NUMA node (since the NUMA node would present itself > logically as having 12 CPUs)?
No, the overcommit ratio is only used when considered the overall load of the system. When deciding whether a guest can fit on a NUMA node, it still uses the actual hardware count. So if a node has 4 CPUs, then a 6 CPU guest will be spread across 2 nodes perhaps 3 CPUs on each node. So with overcommit you could run 4 copies of the guest before the nodes were full according to overcommit ratio. Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :| _______________________________________________ Mailing list: http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack Post to : [email protected] Unsubscribe : http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
