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.
|-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.|