Weird units here → #
Large scale computing just does not work like this. There are so many examples of people who think they can apply 'enterprise' ready solutions to distributed web based apps and have failed - even with basic web sites (see the france.fr debacle for an excellent example).
I mean you no ill will but have been working in this area for many years and you really do have to think in a different manner than simply transactions per seconds.
Some simple examples (some mentioned already in the article). Think in terms of mtbf of kit when you are running a farm that contains as few as 1000 machines. Hardware failures become normal events that you have to engineer for. The idea that you can accept the 4 hours downtime per two years onb your database server and still hit you 99.9% SLA does not apply.
What about backing up 100s of TB of data? A distributed model can eliminate the need for backups.
latency - these database backends also need to return your profile page, your unread messages count and so. Cache solutions need to recalculate.
Creeping death. One node in a cluster goes down, increasing the load on the other nodes and causing the whole lot to go down.
Etc., Etc.