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From Dikang Gu <dikan...@gmail.com>
Subject Re: Questions about the nodetool ring.
Date Tue, 12 Apr 2011 09:43:54 GMT
The 3 nodes were added to the cluster at the same time, so I'm not sure whey
the data vary.

I calculate the tokens and get:
node 0: 0
node 1: 56713727820156410577229101238628035242
node 2: 113427455640312821154458202477256070485

So I should set these tokens to the three nodes?

And during the time I execute the nodetool move commands, can the cassandra
servers serve the front end requests at the same time? Is the data safe?

Thanks.

On Tue, Apr 12, 2011 at 5:15 PM, Jonathan Colby <jonathan.colby@gmail.com>wrote:

> 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
> >
>
>


-- 
Dikang Gu

0086 - 18611140205

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