I wrote an Big Data article [/url]for simple-talk in a similar vein.

Basically, what are the business requirements and how's it going to make money.

Two of the traditional 3Vs of Big Data (Volume, Velocity) are moving targets.

Teradata gets its name because the goal was to be capable of processing 1TB of data back in 1979!

The first actual live 1TB Teradata installation was for Walmart in 1992. As a reference point the HP3000 Series 70 mini-computer I worked on had 670Mb of disk and 8Mb RAM. Teradata WAS Big Data.

These days an iPod Nano is massively more powerful. A mid-range desktop has 2,000x the RAM.

The only one of the Vs that present a constant challenge is "Variety". There are over 50,000 file formats out there containing data and that is before you have to face the challenge of file layouts.