The journey of many businesses from a heavily over subscribed infrastructure solution to the flexible, scalable world of cloud we are in today is a very interesting one. It is still possible to draw parallels between what is now considered to be a highly inefficient approach to building IT solutions, and the practises we still see from some IT suppliers.
In the 2000s it was incredibly common to find an over subscription of hardware when looking at consumption by real workloads. On top of that there would often be a further over subscription for peak periods, especially in e-commerce. This created a double whammy of very high expenditure levels for a given amount of business. The irony was that capacity and spend are relatively interchangeable due to them being commodity infrastructure items.
In the second half of the noughties there was a shift away from the over subscription of hardware. The reason was virtualisation. This allowed businesses to combine and consolidate all of their work loads onto as little hardware as possible. Unfortunately the fact remained, it was still necessary to maintain an overhead of capacity which meant an over subscription for peak periods.