Database Reference
In-Depth Information
WARNING
Be warned that data is not automatically removed from a decommissioned node. If you decide that you
want to reintroduce a previously decommissioned node into the ring with a different range, you'll need
to manually delete its data first.
Updating Nodes
Removing Tokens
If you wish to remove a token, you can do so with Nodetool.
Simply execute the command like this, where the argument to the
removetoken
command is
the actual token you want to remove:
$ bin/nodetool -h 127.0.0.1 removetoken 42218023250148343019074760608074740927
The client will return without comment on success. Note that you cannot remove a node's own
token, as that would destroy the node's integrity. You can connect to node 1 and use it to remove
a given token, wherever it is on the ring.
Compaction Threshold
The compaction threshold refers to the number of SSTables that are in the queue to be com-
pacted before a minor compaction is actually kicked off. By default, the minimum number is 4
and the maximum is 32. You don't want this number to be too small, or Cassandra will spend
time fighting with clients for resources to perform many frequent, unnecessary compactions. You
also don't want this number to be too large, or Cassandra could spend a lot of resources perform-
ing many compactions at once, and therefore will have fewer resources available for clients.
To find out the compaction threshold on a given node, invoke Nodetool with the
getcompac-
tionthreshold
command:
eben@morpheus$
bin/nodetool -h 192.168.1.5 getcompactionthreshold
Current compaction threshold: Min=4, Max=32
Changing Column Families in a Working Cluster
If you need to, you can add, remove, or rename column families in a live Cassandra cluster. Here
are the steps to follow:
1. Using Nodetool, run drainto empty the commit log.
