On Tue, Nov 29, 2016 at 11:59 AM, J. Eric Ivancich <ivancich@xxxxxxxxxx> wrote: > On 11/27/2016 04:50 AM, Byung Su Park wrote: >> P4 >> : To see current QoS quality between clients in the Ceph cluster with >> the pool (LibRADOS) unit based mclock operation queue, we did some tests. >> Although each the client’s moment IO variation was present, under some >> test conditions, a satisfactory QoS result came out in terms of the >> average value. >> (Note that, currently the some IO variation also appears at the default >> WPQ operation queue). >> (Also, additional experimentation and analysis is required with various >> test conditions and issues). >> The specific test environment and result are attached in additional pdf >> file. > > The results look very impressive. I've seen the IO variation in my tests > as well, and it seems unlikely to be due to operation queuing. If you have not also set "osd_op_queue_cut_off = low" in addition to "osd_op_queue = wpq", then you should see much better variation in op latency between clients. There seems to be an issue with snapshots and cut_off low at the moment, so use caution with snapshots. [1] I can't pull up the tracker at the moment to know that status. [1] http://tracker.ceph.com/issues/15774 ---------------- Robert LeBlanc PGP Fingerprint 79A2 9CA4 6CC4 45DD A904 C70E E654 3BB2 FA62 B9F1 -- 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
