On 2020-01-13 14:36, Radoslaw Zarzynski wrote: [skip]
(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 do not understand. I talk about simple comparison metric for any storage application - IOPS. Since both storage applications (legacy-osd, crimson-osd) share absolutely the same Ceph spec - that is a fair choice. For example we do not compare replication protocols (strong consistency vs eventual or weak consistency), or client driven replication vs primary copy replication. These parts in our comparison are the same. But what we compare is how fast message is received and reply is sent back. Nothing more. So what else if not IOPS? If I were a game developer I would probably choose fps :)
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.
Here is my: https://gist.github.com/rouming/dcdca2d6e23fa7ae9041bbda28efd2a1 legacy-osd: ~130MB/s crimson-osd: ~120MB/s BTW prefill writes are also corresponding to reads on my machine: legacy-osd: 122MB/s crimson-osd: 94MB/s What other loads I can try? -- Roman