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From Apache Wiki <wikidi...@apache.org>
Subject [Cassandra Wiki] Update of "Operations" by JonathanEllis
Date Wed, 09 Dec 2009 16:21:59 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 JonathanEllis.
http://wiki.apache.org/cassandra/Operations?action=diff&rev1=9&rev2=10

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  Note that with !RackAwareStrategy, succeeding nodes along the ring should alternate data
centers to avoid hot spots.  For instance, if you have nodes A, B, C, and D in increasing
Token order, and instead of alternating you place A and B in DC1, and C and D in DC2, then
nodes C and A will have disproportionately more data on them because they will be the replica
destination for every Token range in the other data center.
   * The corollary to this is, if you want to start with a single DC and add another later,
when you add the second DC you should add as many nodes as you have in the first rather than
adding a node or two at a time gradually.
  
- Replication strategy may not be changed without wiping your data and starting over.
+ Replication strategy is not intended to be changed once live, but if you are sufficiently
motivated it can be done with some manual effort:
+  1. anticompact each node's primary Range, yielding sstables containing only that Range
data
+  1. copy those sstables to the nodes responsible for extra replicas under the new strategy
+  1. change the strategy and restart
  
  == Network topology ==
  

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