Here's the scenario: you are a business analyst charged with providing reporting and basic analytics on more data than you know how to handle - and you need to do it without the combined resources of your IT department being placed at your disposal. Sounds familiar?
Let's use Point of Sale data as an example as POS data can easily generates more data-volume than the ERP system. The data is simple and easily organized in conventional relational database tables - you have a number of "facts" (sales-revenue, sales-units, inventory, etc.) defined by product, store and day going back a few years and then some additional information about products, stores and time stored in master ("dimension") tables,
The problem is that you have thousands of stores, thousands of products and hundreds (if not thousands) of days -
this can very quickly feel like "big data". Use the right tools and my rough benchmarks suggests you can not only handle the data but see a huge increase in speed.