diagnose lag source?

[zarb]

Hi,

Im running a tekkit 1.0.6 server on fairly resonable server hardware and have a friend plus myself playing on it. The world is now 4 days old and started lagging for both of us pretty badly yesterday.

The lag will occur in spikes (at least once a minute) of maybe 2-5 seconds length and it does not appear to be I/O lag because it doesnt only appear when you interact with inventory blocks (chests/machines). Whenever a lag spike occurs I can see the cpu usage of the server java process climb to 400-700% (whereas 100% means fully utilizing 1 core on linux). I have ran /debug on the server during 2 lag spikes but that appears to be a vanilla command because the interesting parts say "unspecified": http://pastebin.com/j3AQqrNv

Is there any real way to debug/diagnose this lag issue without removing every single block we placed and check if that fixes it?

More notes about the world maybe:

I have restarted the server (process), the lag remains. We also havent created any mystcraft worlds or dimdoors pocket worlds yet. There are however inter-overworld dimdoors. the world has a single chunk loader set to a radius of 1 and 1 turtle running a simple mining program.

Ive never experienced this kind of lag before when playing on my own on the server for like 2 months or whatever it was. So Im assuming its something weird my friend built. Now that theres no ic2 anymore, if cant be wiring loops. The only things I know he made and built that I have never touched before are:

- powersuit glove and placed maybe 50 lights with it

- some weird ME storage system thats like 4x4x4

... and thats really about it

Any pointers?

[weirleader]

any lava pumping in the nether? I would actually expect that to cause continuous lag (if you have a lot of flowing lava), as opposed to spikes, but I'm just starting with my most common lag situation.

[plowmanplow]

One way to combat the "flowing lava lag" problem would be to change this setting:

persistantLava=true (change the true to false)

in the CodeChickenCore.cfg file. This makes lava decay similar to water when it loses contact with a source block.

[zarb]

One way to combat the "flowing lava lag" problem would be to change this setting:

persistantLava=true (change the true to false)

in the CodeChickenCore.cfg file. This makes lava decay similar to water when it loses contact with a source block.

seriously? wow that would make up for the lack of 1.6 (which has the same thing... almost). Thanks a lot for this!

Also I figured it out in the mean time, thanks for your suggestions tho. Turns out it was a leaking DimDoors pocket world, I didnt notice the server console spam until today :|

[Teraku]

Try updating Dimensional Doors, the later versions fix a lot of the lag issues.

[miniboxer]

Try updating Dimensional Doors, the later versions fix a lot of the lag issues.

And make me pee myself.