One of the main design principles in OpenNebula focuses on enabling large scale deployments. In this type of deployment it is usually the case that we have to deal with large number of physical hosts, with the intention of running a large number of virtual machines. This is important since many of the OpenNebula users run large scale deployments with tens of thousands of virtual machines.
The scalability of the virtual infrastructure manager is, without a doubt, a keystone when a large-scale cloud deployment is at stake. The ability to handle a large number of resources, keeping track of them and staying responsive is essential, for that very reason the OpenNebula project has put a lot of effort to make the central component of OpenNebula, the core daemon, as stable and robust a possible.