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From Narendra Sharma <narendra.sha...@gmail.com>
Subject Re: calculating initial_token
Date Tue, 15 Mar 2011 00:04:01 GMT
The %age (owns) is just the arc length in terms of %age of tokens a node
owns out of the total token space. It doesn't reflect the actual data.

The size (load) is the real current load.

-Naren


On Mon, Mar 14, 2011 at 2:59 PM, Sasha Dolgy <sdolgy@gmail.com> wrote:

> ah, you know ... i have been reading it wrong.  the output shows a
> nice fancy column called "Owns" but i've only ever seen the percentage
> ... the amount of data or "load" is even ... doh.  thanks for the
> reply.  cheers
> -sd
>
> On Mon, Mar 14, 2011 at 10:47 PM, Narendra Sharma
> <narendra.sharma@gmail.com> wrote:
> > On the same page there is a section on Load Balance that talks about
> python
> > script to compute tokens. I believe your question is more about assigning
> > new tokens and not compute tokens.
> >
> > 1. "nodetool loadbalance" will result in recomputation of tokens. It will
> > pick tokens based on the load and not the once assigned by you.
> > 2. You can either use decommission and bootstrap with new tokens OR Use
> > "nodetool move"
> >
> > Thanks,
> > Naren
> >
> > On Mon, Mar 14, 2011 at 1:18 PM, Sasha Dolgy <sdolgy@gmail.com> wrote:
> >>
> >> Sorry for being a bit daft ... Wanted a bit of validation or rejection
> ...
> >>
> >> If I have a 6 node cluster, replication factor 2 (don't think this is
> >> applicable to the token decision) is the following sufficient and
> >> correct for determining the tokens:
> >>
> >> #!/bin/bash
> >> for nodes in {0..5};
> >> do
> >>    echo "$nodes*(2^127/5)" | bc;
> >> done
> >>
> >>
> >>
> >>
> >> Gives me a result of:
> >>
> >> 0
> >> 34028236692093846346337460743176821145
> >> 68056473384187692692674921486353642290
> >> 102084710076281539039012382229530463435
> >> 136112946768375385385349842972707284580
> >> 170141183460469231731687303715884105725
> >>
> >> My ring right now is:
> >>
> >>
> >> 10.0.0.2  Up     Normal  225 KB          40.78%
> >> 24053088190195663439419935163232881936
> >> 10.0.0.3    Up     Normal  201.21 KB       19.17%
> >> 56667357399723182105247119364967854254
> >> 10.0.0.4   Up     Normal  213.15 KB       17.61%
> >> 86624712919272143003828971968762407027
> >> 10.0.0.5   Up     Normal  214.54 KB       11.22%
> >> 105714724128406151241468359303513100912
> >> 10.0.0.6  Up     Normal  206.39 KB       5.61%
> >> 115259729732973155360288052970888447854
> >> 10.0.0.7    Up     Normal  247.68 KB       5.61%
> >> 124804735337540159479107746638263794797
> >>
> >> If my new tokens are correct:
> >>
> >> 1.  cassandra.yaml is updated on each node with new token
> >> 2.  node is restarted and a nodetool repair is run, or is a nodetool
> >> loadbalance run
> >>
> >> Thanks in advance ... been staring at
> >> http://wiki.apache.org/cassandra/Operations#Token_selection for too
> >> long
> >>
> >> --
> >> Sasha Dolgy
> >> sasha.dolgy@gmail.com
> >
> >
>
>
>
> --
> Sasha Dolgy
> sasha.dolgy@gmail.com
>

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