Linux virtual machine / host machine filesystem performance
Posted on 2009-07-02
I've seen many benchmarks on filesystem performance, but what I'm wondering is how well a particular filesystem performs in a virtual machine when sitting on top of a different filesystem. In particular I have several VMs running in QEMU/KVM formatted to ext4 running on top of a 5 disk RAID 5 formatted to xfs. Performance is questionable but may be due to other factors such as memory allocation. I'd like to know if this is even an issue, or if keeping host/guest filesystems the same has any performance benefit.