Once server is started, it starts to consume a lot of CPU, slowing down entire system to crawl - and that's with 0 players connected.
It is possible to connect to server, but game is nearly unplayable due to lag.
Update: CPU usage drops after setting server difficulty to peaceful, so most likely the problem is related to hostile mobs (zombies again?).
Related issues
Comments


Bug appears 10 times out of 10 for me.
Could you specify name&version of JRE package you use?
Maybe I'm using wrong JRE.

I've the same problem.
100% CPU usage only at night.
2013-07-02 17:38:06 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-07-02 17:38:41 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-07-02 17:38:45 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-07-02 17:39:30 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-07-02 17:39:34 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
2013-07-02 17:39:55 [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
and so on...

Maybe this can help:
Something's taking too long! 'root.levels.paradise.tick.entities.regular.tick.ai.newAi.goalSelector.goalTick.pathfind' took aprox 261.523724 ms
Something's taking too long! 'root.levels.paradise.tick.entities.regular.tick.ai.newAi.goalSelector.goalTick' took aprox 262.027559 ms
Something's taking too long! 'root.levels.paradise.tick.entities.regular.tick.ai.newAi.goalSelector' took aprox 262.307236 ms
Something's taking too long! 'root.levels.paradise.tick.entities.regular.tick.ai.newAi' took aprox 262.701753 ms
Something's taking too long! 'root.levels.paradise.tick.entities.regular.tick.ai' took aprox 262.92655 ms
Something's taking too long! 'root.levels.paradise.tick.entities.regular.tick' took aprox 263.271346 ms
Something's taking too long! 'root.levels.paradise.tick.entities.regular' took aprox 467.872884 ms
Something's taking too long! 'root.levels.paradise.tick.entities' took aprox 468.349919 ms
Something's taking too long! 'root.levels.paradise.tick' took aprox 473.432748 ms
Something's taking too long! 'root.levels.paradise' took aprox 473.944583 ms
Something's taking too long! 'root.levels' took aprox 474.510017 ms
Something's taking too long! 'root' took aprox 476.359478 ms
Only during nighttime.

Duplicate of MC-17630
Unable to reproduce.