On Sun, Jul 1, 2012 at 11:12 PM, Stefan Priebe - Profihost AG <s.priebe@xxxxxxxxxxxx> wrote: > Am 02.07.2012 07:02, schrieb Alexandre DERUMIER: > >> Hi, >> my 2cent, >> maybe with lower range (like 100MB) of random io, >> you have more chance to aggregate them in 4MB block ? > > > Yes maybe. If you have just a range of 100MB the chance you'll hit the same > 4MB block again is very high. > > @sage / mark > How does the aggregation work? Does it work 4MB blockwise or target node > based? Aggregation is based on the 4MB blocks, and if you've got caching enabled then it's also not going to flush them out to disk very often if you're continuously updating the block — I don't remember all the conditions, but essentially, you'll run into dirty limits and it will asynchronously flush out the data based on a combination of how old it is, and how long it's been since some version of it was stable on disk. On Mon, Jul 2, 2012 at 6:19 AM, Stefan Priebe - Profihost AG <s.priebe@xxxxxxxxxxxx> wrote: > Hello, > > i just want to report back some test results. > > Just some results from a sheepdog test using the same hardware. > > Sheepdog: > > 1 VM: > write: io=12544MB, bw=142678KB/s, iops=35669, runt= 90025msec > read : io=14519MB, bw=165186KB/s, iops=41296, runt= 90003msec > write: io=16520MB, bw=185842KB/s, iops=45, runt= 91026msec > read : io=102936MB, bw=1135MB/s, iops=283, runt= 90684msec > > 2 VMs: > write: io=7042MB, bw=80062KB/s, iops=20015, runt= 90062msec > read : io=8672MB, bw=98661KB/s, iops=24665, runt= 90004msec > write: io=14008MB, bw=157443KB/s, iops=38, runt= 91107msec > read : io=43924MB, bw=498462KB/s, iops=121, runt= 90234msec > > write: io=6048MB, bw=68772KB/s, iops=17192, runt= 90055msec > read : io=9151MB, bw=104107KB/s, iops=26026, runt= 90006msec > write: io=12716MB, bw=142693KB/s, iops=34, runt= 91253msec > read : io=59616MB, bw=675648KB/s, iops=164, runt= 90353msec > > > Ceph: > 2 VMs: > write: io=2234MB, bw=25405KB/s, iops=6351, runt= 90041msec > read : io=4760MB, bw=54156KB/s, iops=13538, runt= 90007msec > write: io=56372MB, bw=638402KB/s, iops=155, runt= 90421msec > read : io=86572MB, bw=981225KB/s, iops=239, runt= 90346msec > > write: io=2222MB, bw=25275KB/s, iops=6318, runt= 90011msec > read : io=4747MB, bw=54000KB/s, iops=13500, runt= 90008msec > write: io=55300MB, bw=626733KB/s, iops=153, runt= 90353msec > read : io=84992MB, bw=965283KB/s, iops=235, runt= 90162msec I can't quite tell what's going on here, can you describe the test in more detail? -- 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
