Hi Kefu, This seems like great progress, and, strongly, concentrating on the 1:1 model feels like a very solid approach. Matt On Fri, Jan 11, 2019 at 9:38 AM kefu chai <tchaikov@xxxxxxxxx> wrote: > > hi, > > want to update you guys with the current status of the crimson-osd. > > where we are: > we have ported/adapted messenger, mon client, config, logging, perf > counter to seastar framework. based on them, we are able to boot[0] > the crimson-osd now. by "boot", i mean, crimson-osd can be discovered > by monitor after it starts. so, we still don't have anything to test > with, aside from the messenger. > > the next steps: > to implement the i/o path to serve the read requests with the memstore > using the 1-to-1 threading model. the reason why we want to prioritize > this is to understand the behavior of crimson-osd as soon as possible > with minimal efforts. so, the focus of current stage of this project > will be: > - the 1:1 mapping implementation. as 1:1 mapping is easier to design > and debugging, and there are a lot valuable insights in the 1:1 versus > m:n discussion. it seems the performance of 1:1 model is not likely to > suffer from any obvious problems. so we think it can be used to > present the best performance we can achieve using share-nothing > architecture. > - read path only. but we need to be sure we don't skip any critical > step that could impact the performance in the i/o path in the future. > this will help us to get an authentic benchmark result. > - memstore only. the access to memstore is practically very fast and > non-blocking.so we can read/write it without worrying about how to > confine bluestore in an alien world and how to cater for its needs for > the facilities only available in alien world. > > once we have the read path ready, and we have a good understanding of > it in the perspective of its performance, and design. we will be > better prepared for implementing the write path and for adding more > features back to crimson-osd. > > as to the methodology of benchmarking, we want to have an > apple-to-apple comparison between crimson-osd and existing osd, we > could start $(npro) instances of crimson-osd side by side, and to > profile it. and on the same box, the same number of existing-osd > instances will be used as the controlled group. > > if i am missing anything or apparently wrong. please point it out. > > thanks, > > -- > [0] https://github.com/ceph/ceph/pull/25304 > > -- > Regards > Kefu Chai -- Matt Benjamin Red Hat, Inc. 315 West Huron Street, Suite 140A Ann Arbor, Michigan 48103 http://www.redhat.com/en/technologies/storage tel. 734-821-5101 fax. 734-769-8938 cel. 734-216-5309
