Originally Posted by
lamer
Cost of parallel backup system: €40 million just to set up.
And useless if you don't regularly test switchovers to the backup system to make sure it works. It's always fun when the online server fails, the system automatically switches to the backup... and it crashes.
As people have said, a lot of this is also probably due to having to build around legacy systems. If you started from scratch, you could build in the redundancy required and ensure it is thoroughly tested from the ground up. It's much harder to bolt that on to an old system that has to be operational 24/7.