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From "cbertu81@libero.it" <cbert...@libero.it>
Subject R: Re: AntiEntropy?
Date Tue, 12 Jul 2011 09:40:12 GMT
>From "Cassandra the definitive guide" - Basic Maintenance - Repair

Running nodetool repair causes Cassandra to execute a Major Compaction [...] 
AntiEntropyService implements the Singleton pattern and defines the static 
Differencer class as well, which is used to compare two trees. If it finds any 
differences, it launches a repair for the ranges that don't agree. So, although 
Cassandra takes care of such matters automatically on occasion you can run it 
yourself as well

So now I'm confused ... Cassandra doc says that I have to run it by myself, 
Cassandra book says I don't have to. 
Did I misunderstand something?


>> I looked around in the code, it seems that AntiEntropy operations are
>> not automatically run in the server daemon, but only
>> manually invoked through nodetool, am I correct?
>
>Yes, and it's important that you do run repair:
>http://wiki.apache.org/cassandra/Operations#Frequency_of_nodetool_repair



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