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From David McNelis <dmcne...@agentisenergy.com>
Subject Re: Partitioning, tokens, and sequential keys
Date Wed, 17 Aug 2011 12:01:33 GMT
Well, I think what  happened was that we had three tokens generated, 0,
567x, and 1134x... but the way that we read the comments in the yaml file,
we just set the second two nodes with the initial token and left the token
for the seed node  blank.  Then we started the seed node, started the other
 two, and then the seed node took on the 613x token.

One question on nodetool ring, the "owns" refers to how many of the possible
keys each node owns, not the actual node size correct?  So you could
technically have a load of 15gb, 60gb, and 15gb on a three node cluster, but
if you have the tokens set correctly each would own 33.33%.

Thanks.

On Tue, Aug 16, 2011 at 3:33 PM, Jonathan Ellis <jbellis@gmail.com> wrote:

> Yes, that looks about right.
>
> Totally baffled how the wiki script could spit out those tokens for a
> 3-node cluster.
>
> On Tue, Aug 16, 2011 at 2:04 PM, David McNelis
> <dmcnelis@agentisenergy.com> wrote:
> > Currently we have the initial_token for the seed node blank, and then the
> > three tokens we ended  up with are:
> > 56713727820156410577229101238628035242
> > 61396109050359754194262152792166260437
> > 113427455640312821154458202477256070485
> > I would assume that we'd want to take the node that
> > is 61396109050359754194262152792166260437 and move it to 0, yes?
> > In theory that should largely balance out our data... or am I missing
> > something there?
> > On Tue, Aug 16, 2011 at 1:54 PM, Jonathan Ellis <jbellis@gmail.com>
> wrote:
> >>
> >> what tokens did you end up using?
> >>
> >> are you sure it's actually due to different amounts of rows?  have you
> >> run cleanup and compact to make sure it's not unused data / obsolete
> >> replicas taking up the space?
> >>
> >> On Tue, Aug 16, 2011 at 1:41 PM, David McNelis
> >> <dmcnelis@agentisenergy.com> wrote:
> >> > We are currently running a three node cluster where we assigned the
> >> > initial
> >> > tokens using the Python script that is in the Wiki, and we're
> currently
> >> > using the Random Partitioner, RF=1, Cassandra 0.8 from the Riptano RPM
> >> > ....however we're seeing one node taken on over 60% of the data as we
> >> > load
> >> > data.
> >> > Our keys are sequential, and can range from 0 to 2^64, though in
> >> > practice
> >> > we're between 1 and 2,000,000,000, with the current  max around
> 50,000.
> >> >   In
> >> > order to balance out the  load would we be best served changing our
> >> > tokens
> >> > to make the top and bottom 1/3rd of the node go to the previous and
> next
> >> > nodes respectively, then running nodetool move?
> >> > Even if we do that, it would seem that we'd likely continue to run
> into
> >> > this
> >> > sort of issue as  we  add  additionally data... would we be better
> >> > served
> >> > with a different Partitioner strategy?  Or will we need to very
> actively
> >> > manage our tokens to avoid getting into an unbalanced situation?
> >> >
> >> > --
> >> > David McNelis
> >> > Lead Software Engineer
> >> > Agentis Energy
> >> > www.agentisenergy.com
> >> > o: 630.359.6395
> >> > c: 219.384.5143
> >> > A Smart Grid technology company focused on helping consumers of energy
> >> > control an often under-managed resource.
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Jonathan Ellis
> >> Project Chair, Apache Cassandra
> >> co-founder of DataStax, the source for professional Cassandra support
> >> http://www.datastax.com
> >
> >
> >
> > --
> > David McNelis
> > Lead Software Engineer
> > Agentis Energy
> > www.agentisenergy.com
> > o: 630.359.6395
> > c: 219.384.5143
> > A Smart Grid technology company focused on helping consumers of energy
> > control an often under-managed resource.
> >
> >
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com
>



-- 
*David McNelis*
Lead Software Engineer
Agentis Energy
www.agentisenergy.com
o: 630.359.6395
c: 219.384.5143

*A Smart Grid technology company focused on helping consumers of energy
control an often under-managed resource.*

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