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Re: [DISCUSS] changing default token behavior for 4.0


+1 to lowering it.
Thanks Jon for starting this.We should create a JIRA to find what other
defaults we need revisit. (Please keep this discussion for "default token"
only.  )

On Fri, Sep 21, 2018 at 8:26 PM Jeff Jirsa <jjirsa@xxxxxxxxx> wrote:

> Also agree it should be lowered, but definitely not to 1, and probably
> something closer to 32 than 4.
>
> --
> Jeff Jirsa
>
>
> > On Sep 21, 2018, at 8:24 PM, Jeremy Hanna <jeremy.hanna1234@xxxxxxxxx>
> wrote:
> >
> > I agree that it should be lowered. What I’ve seen debated a bit in the
> past is the number but I don’t think anyone thinks that it should remain
> 256.
> >
> >> On Sep 21, 2018, at 7:05 PM, Jonathan Haddad <jon@xxxxxxxxxxxxx> wrote:
> >>
> >> One thing that's really, really bothered me for a while is how we
> default
> >> to 256 tokens still.  There's no experienced operator that leaves it as
> is
> >> at this point, meaning the only people using 256 are the poor folks that
> >> just got started using C*.  I've worked with over a hundred clusters in
> the
> >> last couple years, and I think I only worked with one that had lowered
> it
> >> to something else.
> >>
> >> I think it's time we changed the default to 4 (or 8, up for debate).
> >>
> >> To improve the behavior, we need to change a couple other things.  The
> >> allocate_tokens_for_keyspace setting is... odd.  It requires you have a
> >> keyspace already created, which doesn't help on new clusters.  What I'd
> >> like to do is add a new setting, allocate_tokens_for_rf, and set it to
> 3 by
> >> default.
> >>
> >> To handle clusters that are already using 256 tokens, we could prevent
> the
> >> new node from joining unless a -D flag is set to explicitly allow
> >> imbalanced tokens.
> >>
> >> We've agreed to a trunk freeze, but I feel like this is important enough
> >> (and pretty trivial) to do now.  I'd also personally characterize this
> as a
> >> bug fix since 256 is horribly broken when the cluster gets to any
> >> reasonable size, but maybe I'm alone there.
> >>
> >> I honestly can't think of a use case where random tokens is a good
> choice
> >> anymore, so I'd be fine / ecstatic with removing it completely and
> >> requiring either allocate_tokens_for_keyspace (for existing clusters)
> >> or allocate_tokens_for_rf
> >> to be set.
> >>
> >> Thoughts?  Objections?
> >> --
> >> Jon Haddad
> >> http://www.rustyrazorblade.com
> >> twitter: rustyrazorblade
> >
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