When two or more nodes fail at the same time, all nodes can be replaced at the same time as long as one node remains running to act as the node failure recovery control node. However, if both BYNET relay nodes in the database are unavailable during node failure recovery, the database stops. If one or more replacement instances cannot be spun up, the database is brought back up running on Fallback and logons are enabled. If there are two nodes in the same fallback cluster for the AMPs associated with these two nodes, logons are enabled, but queries fail because they reference data from the same fallback cluster where both AMPs are inaccessible. Queries that do not reference data from the failed fallback clusters still work.
If two or more nodes fail at different times while node failure recovery is in progress, contact Teradata Customer Support.