Availability depends on what must stay accessible. In a data pipeline, it means having data ready to feed the system before it runs. For a distributed data store, it means every request receives a valid response, though that response may not contain the latest data. section 6.6 section 16.2
When a network partition forces a choice, a system can cancel an operation to favor consistency or proceed to preserve availability, potentially returning stale data. Pipeline availability is also one of three criteria, alongside reproducibility and consistency. section 16.2 section 6.8



















