3.0 has a (optional?) feature to guarantee better distribution, and the blog focuses on 2.2.
Using fewer will minimize your risk of unavailability if any two hosts fail. -- Jeff Jirsa > On Aug 29, 2018, at 11:18 AM, Max C. <mc_cassan...@core43.com> wrote: > > Hello Everyone, > > Datastax recommends num_tokens = 8 as a sensible default, rather than > num_tokens = 256: > > https://docs.datastax.com/en/dse/5.1/dse-dev/datastax_enterprise/config/configVnodes.html > > … but then I see stories like this (unbalanced cluster when using > num_tokens=12), which are very concerning: > > https://danielparker.me/cassandra/vnodes/tokens/increasing-vnodes-cassandra/ > > We’re currently running 3.0.x, 3 nodes, RF=3, num_tokens=256, spinning disks, > soon to be 2 DCs. My guess is that our cluster will probably not grow > beyond 10 nodes (10 TB?) > > I’d like to minimize the chance of hitting a roadblock down the road due to > having num_tokens set inappropriately. We can change this right now pretty > easily (our dataset is small but growing). Should we switch from 256 to 8? > 32? > > Has anyone had num_tokens = 8 (or similarly small number) and experienced > growing pains? What do you think the recommended setting should be? > > Thanks for the advice. :-) > > - Max >
