Server shuts down after player joins?

Running PaperMC on a local machine that we use on our home LAN. No plugins. It was working fine for the last week or two, then last night it started shutting down 1-2 minutes after someone joins. Didn’t change anything on the server so no idea why this is happening. Looking at the log file, I am not seeing any clear indication of what is causing it. Can someone help? Thanks.

The full log won’t fit here, so I removed the middle chunk to make it fit. Here is a link to the full log: https://pastebin.com/eGTL2dwH

[15:31:34] [User Authenticator #1/INFO]: UUID of player leo487 is 827f89ce-fcc9-3aba-b127-9933602b852f
[15:31:35] [Server thread/INFO]: leo487 joined the game
[15:31:35] [Server thread/INFO]: leo487[/192.168.1.131:56074] logged in with entity id 200 at ([world]40.399723447120465, 63.0, -344.34979406597887)
[15:31:48] [Server thread/WARN]: Can't keep up! Is the server overloaded? Running 12375ms or 247 ticks behind
[15:31:58] [Paper Watchdog Thread/ERROR]: --- DO NOT REPORT THIS TO PAPER - THIS IS NOT A BUG OR A CRASH  - git-Paper-100 (MC: 1.17.1) ---
[15:31:58] [Paper Watchdog Thread/ERROR]: The server has not responded for 10 seconds! Creating thread dump
[15:31:58] [Paper Watchdog Thread/ERROR]: ------------------------------
[15:31:58] [Paper Watchdog Thread/ERROR]: Server thread dump (Look for plugins here before reporting to Paper!):

snip

[15:32:50] [Paper Watchdog Thread/ERROR]: ------------------------------
[15:32:51] [Paper Watchdog Thread/INFO]: Stopping main thread (Ignore any thread death message you see! - DO NOT REPORT THREAD DEATH TO PAPER)
[15:32:51] [Server thread/ERROR]: Main thread terminated by WatchDog due to hard crash
java.lang.ThreadDeath: null
	at java.lang.Thread.stop(Thread.java:939) [?:?]
	at net.minecraft.server.MinecraftServer.stopServer(MinecraftServer.java:947) ~[patched_1.17.1.jar:git-Paper-100]
	at net.minecraft.server.dedicated.DedicatedServer.stopServer(DedicatedServer.java:806) ~[patched_1.17.1.jar:git-Paper-100]
	at net.minecraft.server.MinecraftServer.close(MinecraftServer.java:919) ~[patched_1.17.1.jar:git-Paper-100]
	at org.spigotmc.WatchdogThread.run(WatchdogThread.java:161) ~[patched_1.17.1.jar:git-Paper-100]
[15:32:51] [Paper Watchdog Thread/INFO]: Stopping server
[15:32:51] [Paper Watchdog Thread/INFO]: Saving players
[15:32:51] [Paper Watchdog Thread/INFO]: leo487 lost connection: Server is restarting
[15:32:51] [Paper Watchdog Thread/INFO]: leo487 left the game
[15:32:51] [Paper Watchdog Thread/INFO]: Saving worlds
[15:32:51] [Paper Watchdog Thread/INFO]: Saving chunks for level 'ServerLevel[world]'/minecraft:overworld
[15:32:54] [IO-Worker-84/WARN]: Saving oversized chunk [3, -29] (1064462 bytes} to external file ./world/entities/c.3.-29.mcc
[15:32:54] [Paper Watchdog Thread/INFO]: Saving chunks for level 'ServerLevel[world_nether]'/minecraft:the_nether
[15:32:54] [Paper Watchdog Thread/INFO]: Saving chunks for level 'ServerLevel[world_the_end]'/minecraft:the_end
[15:32:54] [Paper Watchdog Thread/INFO]: ThreadedAnvilChunkStorage (world): All chunks are saved
[15:32:54] [Paper Watchdog Thread/INFO]: ThreadedAnvilChunkStorage (DIM-1): All chunks are saved
[15:32:54] [Paper Watchdog Thread/INFO]: ThreadedAnvilChunkStorage (DIM1): All chunks are saved
[15:32:54] [Paper Watchdog Thread/INFO]: ThreadedAnvilChunkStorage: All dimensions are saved
[15:32:57] [IO-Worker-89/WARN]: Saving oversized chunk [3, -29] (1064462 bytes} to external file ./world/entities/c.3.-29.mcc
[15:32:57] [Paper Watchdog Thread/INFO]: Flushing Chunk IO
[15:32:57] [Paper Watchdog Thread/INFO]: Closing Thread Pool
[15:32:57] [Paper Watchdog Thread/INFO]: Closing Server

Is it possible there are simply a ton of entities where the player is logging in? Or can others log in to the same area?

I don’t think there are a ton of entities. A few animals. But no significant change over when it was working.

Not sure what you mean by this question. Sorry, I’m relatively new to Minecraft. I can say that the server crashes after just 1 player joins, even after a fresh server restart.

  1. How much ram is available to the server? Paper will not do well without enough available RAM. (min. 2G)
  2. Please send a timings report. Just run /timings on, wait a few minutes and then run /timings paste and send the generated link.
    Hint: Change your JVM Flags for more performance: https://mcflags.emc.gs/

The server is running on an actively cooled and overclocked Raspberry Pi 4 with 8GB RAM, Ubuntu Server 64bit booted from an SSD drive (server setup using Cat5TV’s Pinecraft script). Before this issue began, it seemed to run perfectly with no noticeable lag or other issues (tested up to 4 simultaneous players). I just checked and right now (albeit with no players) it is using 2481MB of RAM with 4850MB free.

Here you go: https://timings.aikar.co/?id=0b149e65d25144c1aae5e677c9898318

> timings on
[18:14:33 INFO]: Enabled Timings & Reset
[18:14:34 INFO]: Timings Reset
> timings paste
[18:19:22 INFO]: Preparing Timings Report...
[18:19:23 INFO]: View Timings Report: https://timings.aikar.co/?id=0b149e65d25144c1aae5e677c9898318

I’ll look into this. Thanks.

Anyone able to look at the timings report and offer some insight?

Today, I backed up of the ~/minecraft/world directory on my server and wiped the HDD completely. Then, I installed the server again from scratch and joined the default world. Everything seemed to run just fine. Then, I stopped the server and swapped in the backup of my previous world folder. Booted the server, joined in, and it’s the same exact problem as before. Apparently the issue is within the world itself.

  1. Forgot in my previous reply: Please update to the latest paper version!

  2. The timings report is uncomplete. Start timings and try to join the server. Even if the server crashes it should print the link in the console (im not 100% sure about that).

It seems that way because the server isn’t crashing due to a bug or something.

Try the following:

  1. Take another backup of your world (or skip this part if you haven’t done anything since your last backup)
  2. Delete the world/entities, world_nether/entities, and world_the_end/entities folders.
  3. Start your server again.

If that fixes it, you probably just had too many entities wherever you were trying to log in.

Also note that a Raspberry Pi is really too weak to run a Minecraft server, even with Paper. These are the sorts of problems you get when you try to.

Before we continue I just want to thank @ZombieChickenMan and @ProxyUser for the thoughtful help you both have been providing.

I still don’t fully understand how to interpret the timings report, but it looked to me like the entities were a problem. So, what I did yesterday was delete certain entities from the server console, then I joined the world and deleted more entities (ZombieChickenMan’s advice of deleting the relevant folders would have been a better approach and I’ll try that next time). In particular, I deleted over 50 glow frames and there are still over 50 left (my 5 year old daughter apparently loves putting them all over the house she is building in creative mode). At that point, I was able to join and play without the server shutting down.

I also went in and changed max-tick-time to -1. However, this seems like a “band aid” solution and as such I am not entirely comfortable with it long term.

Here is the latest timings report:
timings.aikar.co/?id=f3877d7eeed1459dacceaac03723aaab
Not sure how helpful it still is since the server has stopped shutting down on its own (after deleting a few dozen entities and setting max-tick-time to -1, as described above).

Yes, I was starting to suspect this as well and this morning I ordered an Optiplex 9020 (Intel i3 4160T @ 3.1GHz, 16GB DDR3 RAM) that I will be running Ubuntu Server (headless) from an SSD. Will this be powerful enough? If not, I have some other projects I can use it for given the small form factor so not a huge loss.

As for the server requirements… It’s really just for my family, usually only 4 simultaneous players or less, maybe 5-7 at the most at some point. I’m less concerned about the player count, which seems low, and more concerned with what will happen if my daughter decides she needs 40 axolotls and 50 glow frames in her house. If possible, I want to avoid being in a situation where I need to strictly police which entities my kids can use and how many.

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While low for a server in general, that will likely be fine for your 4 players, especially as I would doubt your family is going to be building lag machines or needing heavy anti-cheat plugins, etc.

I run a server for my family on a G3220, which has about the same single-thread rating as yours (https://www.cpubenchmark.net/compare/Intel-Pentium-G3220-vs-Intel-i3-4160T/2020vs2380).

50 glow item frames being too much should never be a real problem on competent hardware (no offense to your pi).

As for transferring to the new computer, that will be as simple as copying the folder Paper is installed to (via flash drive, zip and email, whatever) and installing Java 16 from https://adoptium.net/?variant=openjdk16&jvmVariant=hotspot on the new machine.

Since it sounds to me like you don’t have that computer doing anything important, I strongly suggest you install Linux on it as Windows is a poor OS for a Paper server in general and will give you much more trouble with a CPU like that.

Also, as ProxyUser said, you really should update Paper (which is just replacing the old jar file with the new one) as your Timings report shows you’re on a quite outdated build.

Finally, if you have any problems with your new machine (or your old one, for that matter), feel free to ask here, on Discord, or on IRC.

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No offense taken and I appreciate your forthrightness. The RPi4 is a great little machine for a lot of things but apparently not a minecraft server. No worries, I’ll find something else to do with it after I switch to the Optiplex.

Sounds easy, good to know!

The Optiplex 9020 will be a dedicated Minecraft server. And yes, as I mentioned previously, I will be installing Ubuntu server. Headless, so I can stick the box somewhere out of sight (and sound) and manage it remotely without the GUI eating up any precious memory or CPU cycles.

Thanks for letting me know. I installed the server using that automated script I mentioned as it apparently simplifies the server setup process and automatically makes adjustments to optimize for running on the Pi. I guess I assumed it installed the latest version of Paper and never checked.

Thanks! You folks have been very helpful to a noob like me and I appreciate it immensely.

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