> In my production setup, i'm planning to use 2 16G nodes with 750GB disk
> space as Replica Sets and one small node as arbiter ( Total 3 nodes ). My
> data will grow around 500G. I'm not planning to use any sharding here. Do
> you guys see any problems on this design ?
Your general set up sounds standard (replica set with two nodes and an
arbiter) but you'll want to upgrade your disk space before you grow to
500Gb data used of 750Gb total.
The limited amount of free space relative to your data size will be an
issue if you want to do a backup or repair of your database.