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From Sylvain Lebresne <>
Subject Re: Moving to a new cluster
Date Thu, 22 Sep 2011 09:09:38 GMT
2011/9/22 Jonas Borgström <>:
> On 09/22/2011 01:25 AM, aaron morton wrote:
> *snip*
>> When you start a repair it will repair will the other nodes it
>> replicates data with. So you only need to run it every RF nodes. Start
>> it one one, watch the logs to see who it talks to and then start it on
>> the first node it does not talk to. And so on.

This is not totally true because of
Basically, doing this won't make sure the full cluster is in sync
(there is a fair
chance it will, but it's not guaranteed).
It will be true in 1.0 (though in 1.0 it will be simpler and more
efficient to just run
'nodetool repair --partitioner-range' on every node).

> Is this new in 0.8 or has it always been this way?
> From
> """
> Unless your application performs no deletes, it is vital that production
> clusters run nodetool repair periodically on all nodes in the cluster.
> """
> So for a 3 node cluster using RF=3, is it sufficient to run "nodetool
> repair" on one node?

Technically, in the 3 nodes RF=3 case, you would need to do repair on
2 nodes to make sure the cluster has been fully repaired. But it becomes
fairly complicated to know which nodes exactly once you get more than
3 nodes in the cluster or you have RF > 3, so to be safe I would advise
sticking to the wiki instruction (until 1.0 at least).

> / Jonas

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