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From aaron morton <>
Subject Re: Best strategy to increase cluster size and keep nodes balanced
Date Tue, 21 Aug 2012 09:30:28 GMT
Unless you really need to consider moving to 6, it will be easier. 

That said, if you want to get to 7 I would:

* bring the new nodes in with tokens selected for 7.
* move the old nodes to new 7-node tokens. 
* cleanup on the old nodes

There is a way to expedite things by copying files around, _but_ if this is the first time
you have grown the ring I would do it the normal documented way. 

I would make the changes one node at a time. There are a couple of reasons, but here are two:

* if something goes wrong the impact will be less and the cleanup will be less. IMHO With
a cluster of machines it's a good idea to make changes one at a time, so that if / when things
go wrong you get the benefit of the other machines working. 
* bootstrapping new nodes will have some performance impact on the existing nodes. With fewer
existing nodes it will have a larger impact. 

Hope that helps.

Aaron Morton
Freelance Developer

On 21/08/2012, at 12:57 AM, Filippo Diotalevi <> wrote:

> What's the best strategy to increase the cluster size from 3 nodes to 7 nodes, while
keeping the nodes balanced? 
> The datastax documentation at
seems to suggest that it's best practice to add one node at a time. Is it the only approach?
> Can we add 4 new nodes, reset the tokens, and expect the cluster to rebalance correctly?
> Thanks,
> -- 
> Filippo Diotalevi

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