Ok so I have built a pretty typical mob grinder. (4 8×8 spawning pads with a "+" shaped water funneling system three vertical floors of that config water only at the bottom.)
So as I said pretty typical, and functioning, I built a replica in creative with ideal everything. The thing churns 'em out like you would expect.
My question, I built this thing in my factions territory on the craftgasm server. At almost the sky limit. (To cut out the "underground caverns" kryptonite) and spits out mobs at a painfully slow pace. Like slower than what I would expect based off of the vanilla minecraft creative tests. (Even giving it a time handicap, the thing isn't working)
The testing led me to think it was bats. I go up to check, no bats even. I have checked my distance from the spawner, that's not it.
Maybe the server is doing something? Maybe it is set up to prevent hostile mobs from spawning in your territory? Not sure. I put it to you, kind users of the Internet. What are your thoughts?
Best Answer
It is probably not dark enough. Try closing off all entries to the spawners.