I've biked across Asia twice. It's not as easy as you think to get spare parts in many regions. I can't force you to believe what I say, but I highly recommend it.
The OP didn't ask "I am biking across the Gobi Desert, what parts and bike would be the most reliable and have the fewest problems getting parts". I think in 99% of the world he would be fine on disc brakes and is unlikely to have any kind of issues you describe.