On Wed, Feb 4, 2015 at 4:25 AM, Chris Pacejo <cpacejo@xxxxxxxxxxxxxxxx> wrote: > The below observations (including high CPU usage by the OSDs) hold > true when we (roughly) double the performance of the MySQL backend by > pointing it to SSDs instead of rotary media. This causes us to > suspect that our current bottleneck is not the extra load placed on > the backend by the metadata; but rather something in the OSD which > causes it to be unable to saturate the backend. Any thoughts? > Maybe more detail number can help us a bit. > > On Tue, Feb 3, 2015 at 10:13 AM, Chris Pacejo <cpacejo@xxxxxxxxxxxxxxxx> wrote: >> I've instrumented submit_transaction to tick up/down an atomic >> counter. While in certain situations (resource-constrained VM; OSD >> startup), I do see up to "keyvaluestore op threads" number of >> concurrent transaction submits reported by this counter, on real >> hardware, during `rados bench` with 2700-byte objects, I never see >> more than 3 concurrent submits; on average, I see 2. I don't know the >> OSD's internals well enough to speculate on the cause, but it's worth >> noting that the OSD processes consume a lot of CPU (170%+) during >> these benchmarks (compared to 14% for 1 MiB objects). > -- > 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 -- Best Regards, Wheat -- 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
