Removing a node

Use these instructions when you want to remove nodes to reduce the size of your cluster, not for replacing a dead node.

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.

Failure to follow the DSEFS procedure may result in data loss.

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.

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

Use nodetool netstats to monitor the progress.

Decommission does not shutdown the node, shutdown the node after decommission has completed.
If the node is down, choose the appropriate option:
- If the cluster uses vnodes, remove the node using the nodetool removenode command.
- If the cluster does not use vnodes, before running the nodetool removenode command, adjust your tokens to evenly distribute the data across the remaining nodes to avoid creating a hot spot.
If removenode fails, run nodetool assassinate.