Oracle: Why is lag from Minecraft server persisting after server is turned off for multiple hours?
So I use Oracle Cloud Free Tier to host my server currently. My VM has 4 Ocpu and 20 GB of ram. I always allocate 16 or lower to my Minecraft server.
Normally I use Java 19 with the G1GC garbage collector (Aikar's flags).
I want to instead use Java 23 with generational ZGC as my garbage collector.
But for some reason... Every time I run my Minecraft server with ZGC, it's really really speedy and responsive. Until a few hours later it starts slowing down and I start getting messages about watchdog (server taking too long to tick/respond).
So I close the Minecraft server, and restart my VM. But things are not back to normal.
For the next few hours (sometimes days), whether I open the Minecraft server or not, no matter how many times I restart the VM, the VM will remain comedically slow and laggy. The simple act of logging into the VM will take MINUTES instead of fractions of a second. Unzipping a file? Good luck. I can barely even stay connected to the VM.
The only way to fix it is to wait a day or two (it will get fixed even if I don't restart the VM).
Note: Java 19 with G1GC never causes this issue.
Is this just a quirk of Oracle Cloud? Does something about ZGC make Oracle decide to limit my CPU power? Or is my VM just haunted?
Normally I use Java 19 with the G1GC garbage collector (Aikar's flags).
I want to instead use Java 23 with generational ZGC as my garbage collector.
But for some reason... Every time I run my Minecraft server with ZGC, it's really really speedy and responsive. Until a few hours later it starts slowing down and I start getting messages about watchdog (server taking too long to tick/respond).
So I close the Minecraft server, and restart my VM. But things are not back to normal.
For the next few hours (sometimes days), whether I open the Minecraft server or not, no matter how many times I restart the VM, the VM will remain comedically slow and laggy. The simple act of logging into the VM will take MINUTES instead of fractions of a second. Unzipping a file? Good luck. I can barely even stay connected to the VM.
The only way to fix it is to wait a day or two (it will get fixed even if I don't restart the VM).
Note: Java 19 with G1GC never causes this issue.
Why does this happen?
Is this just a quirk of Oracle Cloud? Does something about ZGC make Oracle decide to limit my CPU power? Or is my VM just haunted?
