Durability

Once a transaction has been committed and become durable, it will persist and not be undone. Durability is achieved by completing the transaction with the persistent database system before acknowledging commitment. Provisioning clients only receive SUCCESS responses for transactions that have been successfully committed and have become durable.

The system recovers committed transaction updates in spite of system software or hardware failures. If a failure (for example, loss of power) occurs in the middle of a transaction, the database returns to a consistent state when it is restarted.

Data durability signifies the replication of the provisioned data to different parts of the system before a response is provided for a provisioning transaction. The following additive configurable levels of durability are supported:

1. Durability to the disk on the active provisioning server (for example, just 1)
2. Durability to the local standby server memory (for example, 1 + 2)
3. Durability to the active server memory at the Disaster Recovery site (for example, 1 + 2 + 3)