I am thinking of replacing my 2012 Mac Mini, which is left on all the time, with a 2015 MacBook Air. It would effectively be a desktop replacement and with an external USB drive for my media (same as with my current Mac Mini) it would be perfectly sufficient for my use. I know that the MacBook Air can run in clamshell mode when connected to a monitor/keyboard/mouse. I am just wondering if I can leave it on 24/7 as a server machine without any major harm (this is how my Mac Mini has been running for almost 4 years). The monitor display is ok to go black, but I don't want the machine to go to sleep mode. Thanks!