I'm also experiencing the same issues, see iotop pictures below. I'm running in a KVM virtual machine. Details below. This happened after upgrading to 1.18.1 from 1.17.1. Let me know if you need any more information.
VM Uname: Linux 5.13.0-22-generic #22-Ubuntu SMP Fri Nov 5 13:21:36 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
VM OS: Ubuntu 21.10 Server
Hypervisor: KVM 1:3.1+dfsg-8+deb10u8, running on Debian 10
CPU: Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz (2 cores allocated to VM)
Memory: 16GB total, 6GB allocated to VM
java -version: openjdk version "18-ea" 2022-03-15
OpenJDK Runtime Environment (build 18-ea+15-Ubuntu-4)
OpenJDK 64-Bit Server VM (build 18-ea+15-Ubuntu-4, mixed mode, sharing)
Server start command: /usr/bin/java -Xmx4G -jar minecraft_server.jar nogui
iotop
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iotop -ao for 60 minutes.
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Doing an fatrace, I'm getting the same file r.0.0.mca, I'm also getting writes to r.0.-1.mca as well.
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