[openstack-dev] [Nova] Live Migration: Austin summit update
tdurakov at mirantis.com
Thu May 5 12:34:35 UTC 2016
We've tested live migration of instances under load for following features:
- XBZRLE compression
Tests were done against qemu 2.5. Instances had 2GB ram and stress tool was
used to emulate load:
$ stress -m 1 --vm-bytes 200M --vm-keep
None of them could be called silver-bullet for live-migration process.
Load mentioned above made live-migration process not that stable as
I've also planned to tests all features that Daniel mentioned and it would
to compare results.
On Wed, May 4, 2016 at 11:48 AM, Daniel P. Berrange <berrange at redhat.com>
> On Tue, May 03, 2016 at 04:16:43PM -0600, Chris Friesen wrote:
> > On 05/03/2016 03:14 AM, Daniel P. Berrange wrote:
> > >There are currently many options for live migration with QEMU that can
> > >assist in completion
> > <snip>
> > >Given this I've spent the last week creating an automated test harness
> > >for QEMU upstream which triggers migration with an extreme guest CPU
> > >load and measures the performance impact of these features on the guest,
> > >and whether the migration actually completes.
> > >
> > >I hope to be able to publish the results of this investigation this week
> > >which should facilitate us in deciding which is best to use for
> > >The spoiler though is that all the options are pretty terrible, except
> > >post-copy.
> > Just to be clear, it's not really CPU load that's the issue though,
> > Presumably it would be more accurate to say that the issue is the rate at
> > which unique memory pages are being dirtied and the total number of dirty
> > pages relative to your copy bandwidth.
> > This probably doesn't change the results though...at a high enough dirty
> > rate you either pause the VM to keep it from dirtying more memory or you
> > post-copy migrate and dirty the memory on the destination.
> Yes that's correct - I should have been more explicit. A high rate of
> dirtying memory implies high CPU load, but high CPU load does not imply
> high rate of dirtying memory. My stress test used for benchmarking is
> producing a high rate of dirtying memory.
> |: 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
> OpenStack Development Mailing List (not for usage questions)
> Unsubscribe: OpenStack-dev-request at lists.openstack.org?subject:unsubscribe
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the OpenStack-dev