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Does anyone have experience with Cassandra when nodes go down or are unavailable? I am mostly interested in whether the cluster rebalances and what happens when the nodes come online, or are replaced by new machines.

Bart Kiers
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yazz.com
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1 Answers1

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This is covered in the Operations wiki page: http://wiki.apache.org/cassandra/Operations#Repairing_missing_or_inconsistent_data

jbellis
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  • Thanks, I read it, very technical. Do you know anywhere that explains it in "clear English" as I'm not too bright with these things – yazz.com Feb 16 '10 at 14:21
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    short version: when you tell the cluster that a node is dead permanently, its part of the token ring is given to other nodes and the data is streamed there from other replicas. – jbellis Feb 16 '10 at 14:44
  • ok, thanks, that I understand better. Do you have to tell it "manually" that the node is dead, or can it detect it automatically? – yazz.com Feb 16 '10 at 16:10
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    You have to tell it, because there is no way to tell the difference from the cluster pov between "someone tripped over the power cord and it will be back as soon as it gets plugged back in" and "the motherboard fried." – jbellis Feb 18 '10 at 18:33