On 07/19/2013 04:25 PM, Brian Schott wrote: > I think Soren suggested this way back in Cactus to use MQ for compute > node state rather than database and it was a good idea then. The problem with that approach was the number of queues went exponential as soon as you went beyond simple flavors. Add Capabilities or other criteria and you get an explosion of exchanges to listen to. > On Jul 19, 2013, at 10:52 AM, Boris Pavlovic <boris at pavlovic.me > <mailto:boris at pavlovic.me>> wrote: > >> Hi all, >> >> >> In Mirantis Alexey Ovtchinnikov and me are working on nova scheduler >> improvements. >> >> As far as we can see the problem, now scheduler has two major issues: >> >> 1) Scalability. Factors that contribute to bad scalability are these: >> *) Each compute node every periodic task interval (60 sec by default) >> updates resources state in DB. >> *) On every boot request scheduler has to fetch information about all >> compute nodes from DB. >> >> 2) Flexibility. Flexibility perishes due to problems with: >> *) Addiing new complex resources (such as big lists of complex objects >> e.g. required by PCI Passthrough >> https://review.openstack.org/#/c/34644/5/nova/db/sqlalchemy/models.py) >> *) Using different sources of data in Scheduler for example from >> cinder or ceilometer. >> (as required by Volume Affinity Filter >> https://review.openstack.org/#/c/29343/) >> >> >> We found a simple way to mitigate this issues by avoiding of DB usage >> for host state storage. >> >> A more detailed discussion of the problem state and one of a possible >> solution can be found here: >> >> https://docs.google.com/document/d/1_DRv7it_mwalEZzLy5WO92TJcummpmWL4NWsWf0UWiQ/edit# >> >> >> Best regards, >> Boris Pavlovic >> >> Mirantis Inc. >> >> _______________________________________________ >> OpenStack-dev mailing list >> OpenStack-dev at lists.openstack.org >> <mailto:OpenStack-dev at lists.openstack.org> >> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev > > > > _______________________________________________ > OpenStack-dev mailing list > OpenStack-dev at lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev >