6.02 - Hot Standby Nodes - Teradata Software for Azure

Teradata Vantageā„¢ on Azure (DIY) Installation and Administration Guide

Teradata Vantage on Azure
January 2019

Hot standby nodes (HSNs) are spare, running nodes that improve availability and quickly recover performance levels in the event of a node failure. If one or more nodes fail, the system replaces the failed nodes with the same number of available HSNs.

When launching HSNs, the process automatically tags the new, spare nodes as hsn, distinguishing them from TPA nodes tagged as database. If a TPA node fails, NFR tags the failed node as FailedDatabase and an available HSN replaces it as the new, functional TPA node (database).

TPA or HSN Tag Description
instanceType : database Functional TPA node
instanceType : FailedDatabase Failed TPA node
instanceType : hsn Running HSN
instanceType : TransitioningHSN HSN used for configuration
instanceType : HSNWaiting HSN deployed but not ready to use

You can also deallocate HSNs and switch to traditional NFR, which provisions new TPA nodes to replace failed TPA nodes and takes more time.

If there are no HSNs or not enough available HSNs, NFR automatically spins up one or more replacement nodes, detaches the network-attached storage of the failed node, reattaches the network-attached storage to the new VM, migrates the secondary IPs from the failed node NIC to the new VM NIC, and reinstates the configuration. The replacement node is deployed from a snapshot of the active (control) node.