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From Narendra Sharma <narendra.sha...@gmail.com>
Subject Re: calculating initial_token
Date Mon, 14 Mar 2011 21:47:02 GMT
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
>

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