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From Apache Wiki <wikidi...@apache.org>
Subject [Cassandra Wiki] Update of "Operations" by JuhoMakinen
Date Tue, 31 Aug 2010 12:43:32 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Cassandra Wiki" for change notification.

The "Operations" page has been changed by JuhoMakinen.
http://wiki.apache.org/cassandra/Operations?action=diff&rev1=66&rev2=67

--------------------------------------------------

  As with bootstrap, see [[Streaming]] for how to monitor progress.
  
  === Load balancing ===
+ If you add nodes to your cluster your ring will be unbalanced and only way to get perfect
balance is to compute new tokens for every node and assign them to each node manually by using
nodetool move command.
+ 
+ Here's a python program which can be used to calculate new tokens for the nodes. There's
more info on the subject at Ben Black's presentation at Cassandra Summit 2010. http://www.riptano.com/blog/slides-and-videos-cassandra-summit-2010
+ 
+   def tokens(nodes):                        
+       for i in range(1, nodes + 1):         
+           print (i * (2 ** 127 - 1) / nodes)
+ 
- `nodetool loadbalance`: also essentially a convenience over decommission + bootstrap, only
instead of telling the target node where to move on the ring it will choose its location based
on the same heuristic as Token selection on bootstrap.
+ There's also `nodetool loadbalance`: essentially a convenience over decommission + bootstrap,
only instead of telling the target node where to move on the ring it will choose its location
based on the same heuristic as Token selection on bootstrap. You should not use this as it
doesn't rebalance the entire ring.
  
  The status of move and balancing operations can be monitored using `nodetool` with the `streams`
argument.
  

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