Updating the cluster topology requires at least a quorum of nodes in a cluster to be available. 
If the quorum is lost, it must be restored before you change the cluster topology. 
See :doc:`Handling Node Failures </troubleshooting/handling-node-failures>` for details. 

You can check the status of the nodes in the cluster using the :doc:`nodetool status </operating-scylla/nodetool-commands/status>` command.
