I ran those tests. One of the challenges in benchmarking is to pick the workload, so I chose one our customers do more often. For IO testing I prefer to run FIO tests, and for networking iperf, but unless you do this for a living it is hard to relate to microbenchmarks. It would also leave out the Java settings.
The reason I left the tests running for an hour is because at some point Cassandra gets into compactions, which are CPU and read intensive. The engine memory maps the files, so the IO subsystem backing the storage sees a lot of random IOs as page faults kick in. Streaming IOs get in during fsyncs. Again, easier to see using FIO.
The cluster was brought up at once, and I added the ramp up time on the chart so folks could see it.
I had three goals for this test:
- Show low latency is possible with remote storage and proper capacity planning. This is why I used quorum commit, which forces the client to wait for at least two nodes to commit.
- Share the settings I used. If you open the GIST and download the tarball you'll find all changes I did to the cassandra.yaml and cassandra-env.sh. This benefits our customers directly because it gives them a starting point.
- Recommend that customers look at all samples, not only the middle 80% the stress tool reports. Otherwise the cluster looks much better than it is.
Thank you for the comments! I can assure you I read them, and I'll incorporate suggestions as possible.
The reason I left the tests running for an hour is because at some point Cassandra gets into compactions, which are CPU and read intensive. The engine memory maps the files, so the IO subsystem backing the storage sees a lot of random IOs as page faults kick in. Streaming IOs get in during fsyncs. Again, easier to see using FIO.
The cluster was brought up at once, and I added the ramp up time on the chart so folks could see it.
I had three goals for this test: - Show low latency is possible with remote storage and proper capacity planning. This is why I used quorum commit, which forces the client to wait for at least two nodes to commit. - Share the settings I used. If you open the GIST and download the tarball you'll find all changes I did to the cassandra.yaml and cassandra-env.sh. This benefits our customers directly because it gives them a starting point. - Recommend that customers look at all samples, not only the middle 80% the stress tool reports. Otherwise the cluster looks much better than it is.
Thank you for the comments! I can assure you I read them, and I'll incorporate suggestions as possible.