I think we have a big problem, scheduler is able to allocate more memory than actual physical memory in the compute node, the same statistics are also there in database. For example : if we have a physical memory of 125GB in a node, the total memory allocated to all the instances(virsh dommemstat of all vms) in that host is more than physical memory say around 147GB, being ram_allocation_ratio defined as 1 and reserve_host_memory_mb defined as required. How can nova allocates more memory than actual? Statistics from database +-----------+----------------+-------------+----------------------+ | memory_mb | memory_mb_used | free_ram_mb | ram_allocation_ratio | +-----------+----------------+-------------+----------------------+ | 128897 | 154624 | -25727 | 1 | +-----------+----------------+-------------+----------------------+ we are using openstack stein Regards, Akkina