Mortal Kombat multiplayer servers

Out of curiosity, does anyone know anything about Mortal Kombat servers? I mean, how does it work, is it something that lasts forever ( I mean does the equipment need replacing) and whether there is one main database center, or many in several places?
Idk about MK but Metal Gear Solid shut down after 4 years MK probably will last a good while but nothing is forever especially after the current gen of systems start to drop off in favor of the next cycle...