On Tue, Feb 17, 2015 at 9:37 AM, Mark Nelson <mnelson@xxxxxxxxxx> wrote: > Hi All, > > I wrote up a short document describing some tests I ran recently to look at > how SSD backed OSD performance has changed across our LTS releases. This is > just looking at RADOS performance and not RBD or RGW. It also doesn't offer > any real explanations regarding the results. It's just a first high level > step toward understanding some of the behaviors folks on the mailing list > have reported over the last couple of releases. I hope you find it useful. Do you have any work scheduled to examine the synchronous IO latency changes across versions? I suspect those are involved with the loss of performance some users have reported, and I've not heard any believable theories as to the cause. Since this is the first set of results pointing that way on hardware available for detailed tests I hope we can dig into it. And those per-op latencies are the next thing we'll need to cut down on, since they correspond pretty directly with CPU costs that we want to scale down! :) -Greg -- 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
