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From Apache Wiki <>
Subject [Cassandra Wiki] Update of "Operations" by JonathanEllis
Date Thu, 10 Dec 2009 05:00:33 GMT
Dear Wiki user,

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The "Operations" page has been changed by JonathanEllis.
The comment on this change is: explain modifying RF.


   1. copy those sstables to the nodes responsible for extra replicas under the new strategy
   1. change the strategy and restart
+ Replication factor is not really intended to be changed in a live cluster either, but increasing
it may be done if you (a) use ConsistencyLevel.QUORUM or ALL (depending on your existing replication
factor) to make sure that a replica that actually has the data is consulted, (b) are willing
to accept downtime while anti-entropy repair runs (see below), or (c) are willing to live
with some clients potentially being told no data exists if they read from the new replica
location(s) until repair is done.
+ Reducing replication factor is easily done and only requires running cleanup afterwards
to remove extra replicas.
  == Network topology ==
  Besides datacenters, you can also tell Cassandra which nodes are in the same rack within
a datacenter.  Cassandra will use this to route both reads and data movement for Range changes
to the nearest replicas.  This is configured by a user-pluggable !EndpointSnitch class in
the configuration file.

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