One of the key mistakes people make is labeling their database as a data warehouse solely based on its size. Over the past decade, three phenomena have occurred resulting in major increases in average database size:
The cost of space versus the value of the data has decreased.
Companies now value the data as a critical business asset.
Companies have merged into large multi-national entities.
In other words, the cost of keeping data online is cheap, the perceived value of that data is now very high, and the size of companies and their data needs have grown. As such, many of today's OLTP and ODS databases routinely grow into the 100–800 gigabyte (GB) range. But that does not make them data warehouses. For example, ...