I have been running a Bukkit server since 1.4 was released, with little issue. Today the server locked up, and when I was able to eventually SSH in, Java's CPU load was extremely high. I killed the process, and restarted it, and it has been running since then, but the CPU% according to the 'top' display is about double what I am used to seeing, and the "load average" has been hovering around 1.3-2.3, which isn't exactly ideal. As I will detail below, it looks to me that it caused by something in the world, not plugin. My server: Ubuntu server 64bit (VDS) Java(TM) SE Runtime Environment (build 1.7.0_09-b05) The server is run under SpaceBukkit 1.2rc I had been running Bukkit Beta 1.4.6-R0.3 (Build #02586) since it's release, but while troubleshooting today, updated to Beta 1.4.7-R0.1 (Build #02602). Plugins are fairly limited: SpaceBukkit, RemoteToolkitPlugin, LogBlock, PermissionsEs, WorldEdit, Modifyworld. In troubleshooting the issue, I tried running the server as pure Bukkit, with the 1.4.7 Beta listed above, and no plugins (not even SpaceBukkit), and the load didn't drop at all. I loaded an old backup and ran it with all of the plugins, and the CPU load dropped to a normal range. There are no errors in the log - just constant "Can't keep up!" warnings. Like I said, it looks like the heavy load is due to something that was built in the world recently, or some corruption in the world... since reverting the world is the only thing that has affected the CPU load. But the CPU load remains high even when no players are on the server, so no chunks should be loaded, right? I don't keep daily backups, and I'm not exactly sure when this issue cropped up anyway, since it could have been sitting at a high load for a while before it finally crashed - but the server has been pretty active lately, so I don't want to revert to an old backup unless I really have to. Does anyone have any clue what could be causing the high CPU load, or how I might narrow my search further? I'm completely at a loss. Thanks a lot for any advice!