Bug Description

The server lags severely every few seconds.
The console constantly spams "Can't keep up!",
even though the CPU usage never hits 100%. (usually around 50%-80%).
There are ~6 clients online at a time.

I tried to find issues with the spark profiler (the only change made to the pack)
and found that saving the world takes forever. The generated profile is linker further down.
This performance hit seems to come from some map-hashing.

Did this behavior use to work in the previous version?

Can't tell, we only started playing on the newest version. (3.1.7)

Steps to Reproduce (for bugs)

Play for about 3 Weeks.
Some of us are quite far away from the others.
Some have reached Age 4 others are still in 2.

Logs

• Server Log:
  lastest: https://gist.github.com/Crydsch/4754d6c1705690844726c5d7bee63614
  debug: can't upload, too big. If necessary I'll find another way.
• Crash Log: https://pastebin.com/JqdfU119
• Spark profile: https://spark.lucko.me/#HVASIwaqjW

Client Information

• Modpack Version:
• Java Version: 1.8.0_271-b09
• Launcher Used: MultiMC with recommended java args
• Memory Allocated: differs, 5G-8G
• Server/LAN/Single Player: Selfhosted Server, clients connect over the internet, some over LAN
• Optifine Installed: no
• Shaders Enabled: no

World Information

• Modpack Version world created in: 3.1.7
• Additional Content Installed: only the spark tickprofiler

Server Information

• Java Version: 1.8.0_271-b09
• Operating System: Win10
• Hoster/Hosting Solution: selfhosted
• Sponge (Non-Vanilla Forge) Server: no