On Wed, Sep 23, 2015 at 1:51 PM, Deneau, Tom <tom.deneau@xxxxxxx> wrote: > > >> -----Original Message----- >> From: Gregory Farnum [mailto:gfarnum@xxxxxxxxxx] >> So if you've got 20k objects and 5 OSDs then each OSD is getting ~4k reads >> during this test. Which if I'm reading these properly means OSD-side >> latency is something like 1.5 milliseconds for the single client and...144 >> milliseconds for the two-client case! You might try dumping some of the >> historic ops out of the admin socket and seeing where the time is getting >> spent (is it all on disk accesses?). And trying to reproduce something >> like this workload on your disks without Ceph involved. >> -Greg > > Greg -- > > Not sure how much it matters but in looking at the pools more closely I > was getting mixed up with an earlier experiment with pools that just used 5 osds. > The pools for this example actually distributed across 15 osds on 3 nodes. Okay, so this is running on hard drives, not SSDs. The speed differential is a lot more plausibly in the drive/filesystem/total layout in that case, then... > > What is the recommended command for dumping historic ops out of the admin socket? "ceph daemon osd.<N> dump_historic_ops", I think. "ceph daemon osd.<N> help" will include it in the list, though. -- 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
