Comment 5 for bug 1544017

tgtd eats CPU a lot. With LIO I've got the same results for ephemeral and LVM-based storages inside VM. With tgtd volume performance was ~30-40% slower on my env:

ubuntu@test-ubuntu-vm:~$ dd if=/dev/zero of=/home/ubuntu/testfile bs=1M count=500
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 13.3723 s, 39.2 MB/s

ubuntu@test-ubuntu-vm:~$ sudo dd if=/dev/zero of=/mnt/testfile bs=1M count=500
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 13.3034 s, 39.4 MB/s

NOTE: don't care about speed (39.4 MB/s). My lab is not very fast. It only shows ratio between LVM+LIO and ephemeral storage. This ratio will be similar on the faster envs