Server Can't Keep Up/Time Skipping & Lag

Discussion in 'Spigot Help' started by Zomgrei, Sep 2, 2013.

  1. Hi guys! My first post here, so I was wondering if you all could help me. I'm fairly new to Minecraft server admin, but not new to dealing with Java/JVMs. I was using Craftbukkit (the latest Dev build) and noticed that when I had 5-6 users on spread out in large areas, the server would get the "Can't keep up!" message. The server would lag (hitting mobs would be iffy and time would "skip" backwards a few seconds frequently) and it would generally make it difficult to play. I looked at the JMX console to see the performance of the Craftbukkit JVM specifically, and it was using ~1.5 gigs of the 4 gigs of memory I allocated it and it peaked at less than 80% CPU usage. The machine's CPU usage wasn't much higher than this, as it's a quad-core processor so most of the other tasks running on the server were offloaded to other cores.

    My theory is that the lag is caused because of how spread out the players are (10,000+ blocks away from spawn), but I wonder if the large servers experience this? Is there anything I can do to diagnose the issue/possibly mitigate it?

    Any help or suggestions would be much appreciated!