I have now set both read_promote_adjustment == write_promote_adjustment == 0 and used drop_caches between runs. I also read Documentation/device-mapper/cache-policies.txt at Heinz's suggestion. I'm afraid the performance of the fio test is still not the same as the SSD (4.8 times slower than the SSD-only test now). Would repeated runs of (md5sum virt.* ; echo 3 > /proc/sys/vm/drop_caches) not eventually cause the whole file to be placed on the SSD? It does seem very counter-intuitive if not. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/ _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
