Re: [libvirt-users] HugePages - can't start guest that requires them

Just drop the hard_limit. It's a blackbox we should had never introduced. In Linux, from kernel's POV, there's no difference between guest RAM and hypervisor memory to store its internal state. It's all one big chunk of memory. And even if you know the first part (how much memory you're letting guest to have), you don't know anything about the other part - how much memory does hypervisor need to store its internal state (which may even change over the time), therefore you can't tell the sum of both parts. Also, in the config of your VM, you're not using hugepages. Or you've just posted wrong XML? Then again, kernel's approach to hugepages is not as awesome as to regular system pages. Either on boot (1GB) or at runtime (2MB) one must cut a slice of memory off to be used by hugepages and nothing else. So even if you have ~17GB RAM free on both nodes, they are reserved for hugepages, hence the OOM.