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From aaron morton <aa...@thelastpickle.com>
Subject Re: Moving to a new cluster
Date Sun, 25 Sep 2011 03:24:58 GMT
Thanks sylvain, will look into the new stuff. 



-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com

On 22/09/2011, at 9:09 PM, Sylvain Lebresne wrote:

> 2011/9/22 Jonas Borgström <jonas@borgstrom.se>:
>> 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
> https://issues.apache.org/jira/browse/CASSANDRA-2610.
> 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
>> http://wiki.apache.org/cassandra/Operations#Frequency_of_nodetool_repair
>> 
>> """
>> 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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