On Tuesday, May 22, 2012 at 12:40 PM, Stefan Priebe wrote: > Am 22.05.2012 21:35, schrieb Greg Farnum: > > What does your test look like? With multiple large IOs in flight we can regularly fill up a 1GbE link on our test clusters. With smaller or fewer IOs in flight performance degrades accordingly. > > > > iperf shows 950Mbit/s so this is OK (from KVM host to OSDs) > > sorry: > dd if=/dev/zero of=test bs=4M count=1000; dd if=test of=/dev/null bs=4M > count=1000; > 1000+0 records in > 1000+0 records out > 4194304000 bytes (4,2 GB) copied, 99,7352 s, 42,1 MB/s > > 1000+0 records in > 1000+0 records out > 4194304000 bytes (4,2 GB) copied, 47,4493 s, 88,4 MB/s Huh. That's less than I would expect. Especially since it ought to be going through the page cache. What version of RBD is KVM using here? Can you (from the KVM host) run "rados -p data bench seq 60 -t 1" "rados -p data bench seq 60 -t 16" and paste the final output from both? -- 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
