Hi! I just tried memory overprovisioning with ACS 4.4.3 and KVM on Ubuntu 14.04.
With a ratio of 2.0, a VM configured for 1024MB RAM only sees 512MB RAM (the VM is also running Ubuntu 14.04 with CONFIG_VIRT_BALLOON=y) even if the host is not yet overloaded. This is obviously useless, as I could have configured an offering with 512MB in the first place ;) I can use "virsh setmem" manually to claim the full 1024MB. I would expect to have the 1024MB unless the host is overloaded, in which case the VMs are reduced proportionally (as XenServer does it) or based on actual usage. There are lots of threads and wiki pages on memory overcommit or memory overprovisioning, but most seem outdated or incomplete. Is such a behaviour possible with current CloudStack, libvirt and KVM? Thanks Martin
