Virtualization is no longer a trend, it's simply the reality in nearly every data center, especially the ones that are
newly built. And it makes sense, too: These days, Computers have such an insane amount of processing power that no one
single user will ever be able to use it to full capacity. (Check your load average if you don't believe me. Tip: 100%
is usually equal to the number of CPU cores
But if you're running a multitude of virtual machines on a single hardware, that hardware has to be able to take the load.
With regard to CPU and RAM, that's easy: Just buy enough of 'em. In terms of network bandwidth that works too, a simple
Gigabit connection can already get you quite far, and ten gigabit ethernet is readily available.
Unfortunately, it's not that easy when it comes to storage. Scaling up a single system can get pretty expensive beyond a
certain point, and you don't want to build yourself a very expensive single point of failure. Scaling out
to a bunch'a systems is fair enough regarding the price, but at the end of the day, it always comes down to a single user
waiting for a single disk to do stuff, so this approach does not do anything to increase that particular user's experienced
So in order to speed that up, we'll go and buy some SSDs, right?