Removing a node

Reduce the size of a datacenter.

Use these instructions when you want to remove nodes to reduce the size of your cluster, not for replacing a dead node.
Attention: If you are not using Virtual nodes (vnodes), you must rebalance the cluster.

Prerequisites

If the node is a DSEFS node, follow this alternative node removal procedure: Removing a DSEFS node.
Warning: Failure to follow the DSEFS procedure may result in data loss.

Procedure

  • Check whether the node is up or down using nodetool status:

    The nodetool command shows the status of the node (UN=up, DN=down):

  • If the node is up, run nodetool decommission.

    This assigns the ranges that the node was responsible for to other nodes and replicates the data appropriately.

    Note: To avoid excessive data streaming, make node topology changes one at a time.

    Use nodetool netstats to monitor the progress.

    Note: Decommission does not shutdown the node, shutdown the node after decommission has completed.
  • If the node is down, choose the appropriate option:
  • If removenode fails, run nodetool assassinate.