The Ingestion Box in the reference architecture is displayed as the smallest box. However, this is the component that integrates with all the available data sources. This tends to be among the most complex and time consuming task, but tends to be relegated to a lower priority which is a big mistake.
One needs to prioritize the data sources that generate maximum value and ensure we can ingest the data into the Big Data platform for subsequent “cool” analytics.
In my experience, it is also extremely important to have a robust User Interface for the ingestion section. Otherwise, there could be a series of manual steps leading to errors and ingestion of “bad” data that will minimize impact of subsequent analytics.