Just to close the loop on this, https://issues.apache.org/jira/browse/CASSANDRA-13701 is getting tested now. The project testing will get updated to utilize the new defaults (both num_tokens and using the new allocation algorithm by uncommenting allocate_tokens_for_local_replication_factor: 3. Jon did some documentation on num_tokens on https://cassandra.apache.org/doc/latest/getting_started/production.html#tokens on a separate ticket he mentioned - https://issues.apache.org/jira/browse/CASSANDRA-15600. The new default in Cassandra 4.0+ will be to use the new allocation algorithm with num_tokens: 16. There is a note in the NEWS.txt about upgrading and bootstrapping. It is a lot of effort to change this once it is set, so hopefully new users will be in a much better place out of the box. Thanks everyone for your efforts in this.
On Wed, Apr 1, 2020 at 4:28 PM Jeremy Hanna <jeremy.hanna1...@gmail.com> wrote: > As discussed, let's go with 16. Speaking with Anthony privately as well, > I had forgotten that some of the analysis that Branimir had initially done > on the skew and allocation may have been internal to DataStax so I should > have mentioned that previously. Thanks to Mick, Alex, and Anthony for > doing this analysis and helping back the decision with data. This will > benefit many that start with Cassandra that don't know that 256 is a bad > number and end up with a hard to change decision later. I assigned myself > to https://issues.apache.org/jira/browse/CASSANDRA-13701. Thanks all. > > On Wed, Mar 11, 2020 at 6:02 AM Mick Semb Wever <m...@apache.org> wrote: > >> >> >> > I propose we drop it to 16 immediately. I'll add the production docs >> > in CASSANDRA-15618 with notes on token count, the reasons why you'd >> want 1, >> > 4, or 16. As a follow up, if we can get a token simulation written we >> can >> > try all sorts of topologies with whatever token algorithms we want. >> Once >> > that simulation is written and we've got some reports we can revisit. >> >> >> This works for me, for our first step forward. >> Good docs will always empower users more than any default setting can! >> >> cheers, >> Mick >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: dev-unsubscr...@cassandra.apache.org >> For additional commands, e-mail: dev-h...@cassandra.apache.org >> >>
