How should I go about changing command line arguments to KVM? Things like cache=none or cache=writethrough.
I noticed that the swap uses cache=off : shouldn't it be cache=none (Ubuntu 12.04)?
Also how can I set cache=none or cache=writeback for the main LV which is mounted as root on the VM.
And yes I know cache=writeback may not be a good idea, but my KVMs have such slow IO Performance (only about 1/3 of the host) that I am desperate for some improvement.
The host is a quad core i7 with 32GB memory and software Raid-1 (2 x 3 TB) running Ubuntu 12.04. The VMs are also running Ubuntu 12.04.