Hi Roman, On Sat, Jan 11, 2020 at 4:49 PM Roman Penyaev <rpenyaev@suse.de> wrote:
Then taking into account everything you've said what load is a win for crimson? What exactly should I run to notice that all shiny things which seastar provides actually work and bring a value?
I usually go with 4 KB random reads using `rados bench`. For the main path It should generate workload very similar to RBD while being much more efficient generator than FIO. The former requires a fair amount of CPUs which can be restricting when doing quick dev tests with multiple instances (crimson requires at least two to saturate) on a HW with limited CPU count.
(and I talk about iops, because that's actually what matters for storage after all).
This requires clarification. IOPS from single OSD instance or from a set of HW? I think that all finally matters is return-on-investment. Number of processes inside a box is an implementation detail.
I just want to run a simple benchmark, which can show me a clear difference in iops numbers between legacy and crimson osd.
Sure. Currently we have the `perf check bot` doing `scripts/run-cbt.sh` on `crimson-osd` to hunt for regressions. However, deploying environment might be a bit time-consuming, so I quickly & roughly compared both OSD implementations in the old school way: https://gist.github.com/rzarzynski/9f92f951c929d4a4ed9a7a13ff156b71 All commands all there. I would be grateful for verifying the results. Regards, Radek