Hello list,i've made some further testing and have the problem that ceph doesn't scale for me. I added a 4th osd server to my existing 3 node osd cluster. I also reformated all to be able to start with a clean system.
While doing random 4k writes from two VMs i see about 8% idle on the osd servers (Single Intel Xeon E5 8 cores 3,6Ghz). I believe that this is the limiting factor and also the reason why i don't see any improvement by adding osd servers.
3 nodes: 2VMS: 7000 IOp/s 4k writes osds: 7-15% idle 4 nodes: 2VMS: 7500 IOp/s 4k writes osds: 7-15% idleEven the cpu is not the limiting factor i think it would be really important to lower the CPU usage while doing 4k writes. The CPU is only used by the ceph-osd process. I see nearly no usage by other processes (only 5% by kworker and 5% flush).
Could somebody recommand me a way to debug this? So we know where all this CPU usage goes?
Stefan -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html