6.02.6.02 - 6.02 - Rebuild AMPs after Failure - Teradata Software for Azure

Teradata® Software for Azure Installation and Administration Guide

prodname
Teradata Software for Azure
vrm_release
6.02
category
Administration
Configuration
Installation
featnum
B035-2810-128K

If a Teradata system with local storage loses a node, it also loses the portion of the database kept on the AMPs. When Teradata brings up a replacement node, the AMPs appear in FATAL state. Fallback is enabled by default on all tables so data is maintained in Fallback rows on the other AMPs until the AMP is rebuilt on the replacement node. The AMP rebuild process restores the data for the lost AMPs and brings the AMPs back online.

The length of time to rebuild AMPs depends on how much data must be copied and how much other work the database is doing while the rebuild is in progress. Consider scheduling rebuilds at times that minimally impact users. You can start the rebuild and check progress at regular intervals, such as every hour.

Before starting the AMP rebuild process, the database must be operational. The rebuild process brings up the database if it is down, but if the problem prevents the database from starting, it must be fixed before the rebuild can begin.

The rebuild stops and restarts the database at the time of initiation and completion. If the database restarts for other reasons while a rebuild it running, you must rerun the script after the database is back up to resume the rebuild. If the script is running in wait mode when a restart occurs, you must cancel and restart it.
Argument Description
-w Known as wait mode; Keeps the script running without further interaction until AMPs are back online. Use alone or with -t.
-t Changes the interval between display of rebuild progress messages from the default value of 4 seconds. Append this option with the number of seconds you want to elapse between status messages. For example, type -wt 20 to display the status every 20 seconds.
Ctrl-c Pauses the rebuild temporarily. Enter # tdc-rebuild to restart the script.
-c Cancels the rebuild process completely.