Add Reserve Nodes

This section explains how to add reserve nodes to a cluster in an on-premises Exasol 8 deployment.

In an on-premises installation of Exasol you can have one or more reserve nodes standing by for the active nodes, also known as hot standby. If a node fails, a reserve node immediately takes over for the failed node and the cluster operating system restarts services on the new node. For more information about the failover mechanisms in Exasol, see Fail Safety.

In the current version of Exasol 8 you cannot define nodes as reserve nodes in the configuration when you create a deployment. Instead, you must first create a deployment with only data nodes, and then add nodes that are defined as reserve nodes.

For information about this procedure, see Add Reserve Nodes to Existing Deployment

It is not possible to remove active nodes from an Exasol database. If you want to reduce the number of active data nodes in a cluster you must delete the database and the data volume and create a new deployment.