[1.12.2]Lag on server.

[VolcanoHands]

Hello!

I'm having a lot issues with lag on my server and I can't figure out why. I'm using a VPS to host a server for me and a few friends, the only mods we have installed are OpenTerrainGen, Biome Bundle and AI Improvements(Was suggested as a fix to the lag). The second a 4th person joins the server, the TPS gets real bad and the console is filled with those "Can't keep up!" messages. I ran a server earlier this year, 1.11.2, with the same mods and same VPS without any issues at all so I'm struggling to figure out what the issue is now. I've only tried the newest and the recommended versions of 1.12.2 forge yet, but both produce the same amount of lag. Going to vanilla removes all lag. I used pregen at first to load up the world to reduce stress on the server when we explore later on. View Distance is set to 12.

 

Here is the latest JVM argument I tried java -Xmx6g -Xms6g -XX:+UseG1GC -XX:ParallelGCThreads=4 -XX:-UseAdaptiveSizePolicy -Xmn128M -jar forge-1.12.2-14.23.1.2566-universal.jar nogui but there really is no difference between this and the normal one.

 

This is the only picture I have of any TPS related thingies atm https://imgur.com/8x7bK1R

 

Any help is appreciated.  

Edited December 20, 2017 by VolcanoHands

[VolcanoHands]

3 minutes ago, diesieben07 said:

What kind of hardware is the server using? Are the players close to each other, or far spread out? Is new terrain being generated while this happens?

It's a four core CPU, not sure which, with 12gb of ram and an SSD for storage. A few people are a few hundred blocks away from spawn and the rest of us are close to each other. I generated 6000x6000, about 200 chunks, before we started playing, nobody has been that far yet. On the 1.11.2 server we had, same specs and same situation with players being a bit spread out, we had no lag at all.

[VolcanoHands]

1 hour ago, diesieben07 said:

Now you are speaking as if there were more than 4 people on the server.

Just "4 cores" can mean anything. A 4-core high-end, modern Intel CPU will blow a 4 core CPU from 5 years ago to pieces.

 

Your screenshot shows the main server thread as the highest consumer of CPU time. You should run the debug command to find potential bottlenecks.

I might have worded myself poorly. We are group of 7 or so people, but the lag starts when a 4th person joins the server. With 4 people online the block lag is about two seconds, and with 5 online it is just unplayable.

 

The VPS uses a Xeon e5-2630. The very same CPU ran these mods fine on 1.11.2, and vanilla 1.12.2 runs just fine. I can't really imagine that just forge and OTG would be enough to put the CPU under enough stress to cause this kind of lag.

 

Here is the results from the debug I ran with 4 people online.https://pastebin.com/HmzGutxJ

[VolcanoHands]

We don't as far as I can see. The lag has been here ever since we spawned in, so it's at least not something we've made ourself, and the world works just fine in vanilla.