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The "Operations" page has been changed by gdusbabek. http://wiki.apache.org/cassandra/Operations?action=diff&rev1=31&rev2=32 -------------------------------------------------- Cassandra is smart enough to transfer data from the nearest source node(s), if your !EndpointSnitch is configured correctly. So, the new node doesn't need to be in the same datacenter as the primary replica for the Range it is bootstrapping into, as long as another replica is in the datacenter with the new one. + Bootstrap progress can be monitored using `nodetool` with the `streams` argument. + == Moving or Removing nodes == - === Removing nodes entirely === You can take a node out of the cluster with `nodetool decommission` to a live node, or `nodetool removetoken` (to any other machine) to remove a dead one. This will assign the ranges the old node was responsible for to other nodes, and replicate the appropriate data there. @@ -77, +78 @@ === Load balancing === `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. + + The status of move and balancing operations can be monitored using `nodetool` with the `streams` argument. == Consistency == Cassandra allows clients to specify the desired consistency level on reads and writes. (See [[API]].) If R + W > N, where R, W, and N are respectively the read replica count, the write replica count, and the replication factor, all client reads will see the most recent write. Otherwise, readers '''may''' see older versions, for periods of typically a few ms; this is called "eventual consistency." See http://www.allthingsdistributed.com/2008/12/eventually_consistent.html and http://queue.acm.org/detail.cfm?id=1466448 for more.
