Hi Folks > Yi Thank you for your summarization. I'm start feeling we should separate topics of scalability and HA here. Actually, nova-scheduler only deals scalability part. so definition of "scheduler" this context is " decide host of resources " A resource contains VM, Volume, dhcp-agent, l3-agent, loadbalancer etc. we can also define HA-resource with many method. For instance , ha-l3-agent, vrrp-l3-agent ,heartbeat-ha-dhcp-agent, so I suppose we can discuss HA and scalability separately. 2012/12/6 Yi Yang (yiya) <yiya at cisco.com> > Scalability -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openstack.org/pipermail/openstack-dev/attachments/20121211/5235f3a2/attachment.html>