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From Jonathan Colby <jonathan.co...@gmail.com>
Subject Re: Questions about the nodetool ring.
Date Tue, 12 Apr 2011 09:15:31 GMT
This is "normal" when you just add single nodes.   When no token is assigned, the new node
takes a portion of the ring from the most heavily loaded node.    As a consequence of this,
the nodes will be out of balance.

In other words, when you double the amount nodes you would not have this problem.

The best way to rebalance the cluster is to generate new tokens and use the nodetool move
<new-token> command to rebalance the nodes, one at a time.

After rebalancing you can run "cleanup" so the nodes get rid of data they no longer are responsible
for.

links:

http://wiki.apache.org/cassandra/Operations#Range_changes

http://wiki.apache.org/cassandra/Operations#Moving_or_Removing_nodes

http://www.datastax.com/docs/0.7/operations/clustering#adding-capacity



On Apr 12, 2011, at 11:00 AM, Dikang Gu wrote:

> I have 3 cassandra 0.7.4 nodes in a cluster, and I get the ring stats:
> 
> [root@yun-phy2 apache-cassandra-0.7.4]# bin/nodetool -h 192.168.1.28 -p 8090 ring
> Address         Status State   Load            Owns    Token                        
              
>                                                        109028275973926493413574716008500203721
    
> 192.168.1.25    Up     Normal  157.25 MB       69.92%  57856537434773737201679995572503935972
     
> 192.168.1.27    Up     Normal  201.71 MB       24.28%  99165710459060760249270263771474737125
     
> 192.168.1.28    Up     Normal  68.12 MB        5.80%   109028275973926493413574716008500203721
> 
> The load and owns vary on each node, is this normal?  And is there a way to balance the
three nodes?
> 
> Thanks.
> 
> -- 
> Dikang Gu
> 
> 0086 - 18611140205
> 


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