+1 to adding the feature, clear and easy configurability, and if after a major cycle we can say with confidence it's beating the status quo in the vast majority of general cases, flip default. I mean, logically it *should* be, but infra software at the scale we do requires great care. :)
This is great work Amit - well done. On Mon, Oct 16, 2023, at 4:28 PM, Dinesh Joshi wrote: > I haven't looked at the patch yet so take whatever I say here with a pinch of > salt. > > Philosophically, defaults should not change unless there is a clear > demonstrable benefit in majority cases for our users. In this case DirectIO > should have clear benefits. That said, this is a new feature and I would > personally default it to off. We should document it and allow for our users > to enable it. This derisks the project in case there is an inadvertent change > in behavior. > > Dinesh > >> On Oct 15, 2023, at 11:34 PM, Pawar, Amit <amit.pa...@amd.com> wrote: >> >> [Public] >> >> >> Hi, >> >> CommitLog uses mmap (memory mapped ) segments by default. Direct-IO feature >> is proposed through new PR[1] to improve the CommitLog IO speed. Enabling >> this by default could be useful feature to address IO bottleneck seen during >> peak load. >> >> Need your input regarding changing this default. Please suggest. >> >> https://issues.apache.org/jira/browse/CASSANDRA-18464 >> >> thanks, >> Amit Pawar >> >> [1] - https://github.com/apache/cassandra/pull/2777
