Teradata Database Fold and Unfold
You can add or remove nodes from an existing system. Adding nodes is referred to as unfolding. Removing nodes is referred to as folding. Folding and unfolding supports only EBS data storage. See Teradata Database Instance Types. A system can always be folded back after unfolding. This feature only applies to the Advanced and Enterprise tiers.
- Increases the performance of the system by adding more CPU and memory, and increases the storage bandwidth by decreasing the data volumes managed per node.
- Increases the node count by provisioning additional instances and other resources causing an increase in infrastructure and software costs.
- Consumes additional subnet space. The subnet must have enough IP addresses for the new instances being added to the system. See COP Entries.
- Migrates EBS data volumes from existing instances to new instances.
- Decreases the performance of the system by removing CPU and memory, and decreases the storage bandwidth by increasing the data volumes managed per node.
- Decreases the node count by terminating instances that are no longer needed and associated resources causing a decrease in infrastructure and software costs.
- Migrates EBS data volumes from the nodes that are removed to the remaining nodes.
The database capacity and AMP count does not change. When folding and unfolding, the number of AMPs gets redistributed evenly across the nodes.
If either fold or unfold cannot complete successfully, the process automatically attempts to roll back the operation and restore the original configuration. If roll back fails, contact Teradata Customer Support.
For troubleshooting information on BYOL, see Licensing Issues During Fold and Unfold.