Am 11.06.2014 12:41, schrieb thegeezer: >> everything around 380 MB/s ... only ~350 MB/s for >> /dev/vg01/winserver_disk0 (which still is nice) > > > OK here is the clue. > if the LVs are also showing such fast speed, then please can you show > your command that you are trying to run that is so slow ?
I originally noticed that virt-backup was slow so I looked into it and found some dd-command. My tests right now are like this: booze ~ # dd if=/dev/vg01/winserver_disk0 bs=1M of=/dev/null ^C25+0 Datensätze ein 24+0 Datensätze aus 25165824 Bytes (25 MB) kopiert, 13,8039 s, 1,8 MB/s booze ~ # dd if=/dev/vg01/winserver_disk0 bs=4M of=/dev/null ^C6+0 Datensätze ein 5+0 Datensätze aus 20971520 Bytes (21 MB) kopiert, 12,5837 s, 1,7 MB/s booze ~ # dd if=/dev/vg01/winserver_disk0 of=/dev/null ^C55009+0 Datensätze ein 55008+0 Datensätze aus 28164096 Bytes (28 MB) kopiert, 12,611 s, 2,2 MB/s So no "copy from-to same disk here" ... should be just plain reading, right? virt-backup does some ionice-stuff as well, but as you see, my test-commands don't. # cat /sys/block/sdc/queue/scheduler [noop] deadline cfq -> noop scheduler to let the controller do its own scheduling thanks, Stefan
