Active Standby Nodes
An active standby node is a specialized type of Vertica node. An active standby node exists as a backup node, ready to replace a failed node. Unlike standard Vertica nodes, an active standby node does not perform computations or contain data. If a standard(permanent) node fails, an active standby node can replace the failed node, after the failed node exceeds the failover time limit. When it take the place of a failed node, the active standby node contains all of the projections and performs all of the calculations of the replaced node.
To deploy active standby nodes automatically, you must first configure the FailoverToStandbyAfter parameter. If possible, Vertica selects a standby node from the same fault group as the failed node. Otherwise, Vertica randomly selects an available active standby node.
If you are an administrator, you can manually replace a failed node using the ALTER NODE command. You can specify a particular standby node to replace a failed node, or you can allow Vertica to choose a node. As with automatic node replacement, Vertica defaults to a standby node from the same fault group as the failed node. If the fault group has no available standby nodes, Vertica selects any available active standby node.