Hi Mark. Thanks for answering. I tested the performance on Samsung NVMe SSD 960 PRO 512GB, 2-way E5-2650(2.2GHz, 12-core) CPU , not HDD... Is it a problem that I check the performance on ceph that is deployed by 'vstart'..? Please tell me how to deploy ceph to achieve similar results..! Thank you Shin ᐧ 2021년 8월 19일 (목) 오후 3:55, Mark Nelson <mnelson@xxxxxxxxxx>님이 작성: > On 8/18/21 9:22 PM, 신희원 / 학생 / 컴퓨터공학부 wrote: > > Hi, > > > > I measured the performance of ceph-osd and crimson-osd with same single > > core affinity. > > I checked IOPS, Latency by rados-bench write , and crimson-osd has lower > > performance than ceph-osd about 3 times. (ceph-osd(BlueStore): 228 IOPS, > > crimson-osd(AlienStore): 73 IOPS) > > -> " $ rados bench -p rbd 10 write --no-cleanup " > > > > Then, crimson-osd's CPU utilization is almost 100%. > > I think this is the reason of performance degradation.. > > > > Crimson-osd is known for lower CPU consumption than ceph-osd. > > I wonder why crimson-osd has more CPU usage in this experiment. > > > > Please let me know how to fix it, > > > > Shin > > > Those are pretty low numbers in general. Is that on HDD? You are > correct that crimson right now is only using a single reactor core. > That means that tests done with cyanstore will (almost!) always be > limited to ~100% CPU usage. With alienstore you'll still have bluestore > worker threads, but we are often still limited by work being done in the > reactor thread. Here's the most recent performance data we've got > internally (from a ~july build of crimson-osd vs ceph-osd) on NVMe > drives using fio: > > > > https://docs.google.com/spreadsheets/d/1AXj9h0yDc2ztFWuptqcTrNU2Ui3wMyAn6QUft3CPdcc/edit?usp=sharing > > > The gist of it is that on the read path, crimson+cyanstore is > significantly more efficient than crimson+alienstore and any classic > setup. We are slower in terms of absolute performance, but that's > expected to be the case until the multi-reactor work is done. The > thinking right now is that we probably have some optimization we can do > alienstore and of course bluestore as well (We have ongoing work > there). On the write path things are a little murkier. Cyanstore for > some reason is more efficient with very small and very large datasets > but not the middle size case. alienstore/bluestore and classic memstore > efficiency seems to drop overall as the dataset size grows. In fact > classic memstore is significantly less efficient on the write path than > bluestore is and this isn't the first dataset to show this. > > > I guess all of this is a round about way of saying that you are testing > very "wild west" code right now. 73 iops is pretty abysmal, but if this > is on HDD you might be the only person that's ever tried > crimson+alienstore+hdd so far. We might be more sensitive to backend > latency on HDD with crimson+alienstore, but that's just a guess. > > > Mark > > > > ᐧ > > _______________________________________________ > > ceph-users mailing list -- ceph-users@xxxxxxx > > To unsubscribe send an email to ceph-users-leave@xxxxxxx > > _______________________________________________ > ceph-users mailing list -- ceph-users@xxxxxxx > To unsubscribe send an email to ceph-users-leave@xxxxxxx > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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