Test Tux
Comments
@Pierre Waldén: You seem to be pretty familiar with the Minecraft software. Do you know, what happens (on the side of the client) when one goes through a nether portal or tries to log on to the server? I had some time to do some testing in the last days and here are my observations:
A friend of mine who is connected over the internet to my server (while I am connected to my server via a single cable and switch since my server is in my room)
Unlike others, I don't suddenly get kicked off the server. I can play as long as I want until I decide to go through a nether portal
Once connection is lost, any attempt to reconnect without restarting the client fails
If I log on to my server and disconnect immediately after successful login, I can't login again. I have to restart my minecraft client
When I start a world in single player mode and then decide to play in multiplayer mode, I can't connect. I get another error message (connection reset by peer). I have to restart the client to log on to my server
When playing minecraft, my CPU (Intel core i3, 2x2,5 GHz) on my computer which runs the Minecraft client is at about 30-40% load. However, if I go through the nether portal (or try to reconnect without restarting the client) one of the CPU gets stuck at 100% until I lose my connection
The timeout exception only happens when playing under Linux (debain 7.0 wheezy). Under windows (same computer) the problem does not happen. However, I get more frames per second when playing under Linux, therefore I prefer Linux
The viewing distance on my server is set to 10. In general, All the server settings (except for the difficulty, which I manually set to 2 = normal) are default values.
I would appreciate any help and suggestions where to look further or which tests to conduct in order to isolate or even fix the problem
Well, indeed there seem to be many reasons for this error message to appear. However, I do agree with Kyle Lane that something must have changed in 1.8, since I previously did not get this error message at all.
Furthermore, I would concloud that in my case the error is on the client side, since my friend, who is connected to my server via the internet, does not experience this problem. So I would rule out a corrupted map, too many mobs/animals, a crappy server and problems with the ISP. Is this conclusion reasonable?
I found out, that if I run the client on Windows, I don't get this error message. It only happens if I play minecraft on Linux (debian wheezy). However, I get a higher fps and smoother overall graphics experience on Linux.
Pierre Waldén: I haven't tried tabbing out or doing something else (like watching youtube) yet, since I have my second computer (which also runs the server) for these purposes. What do you excactly mean by "increase the rate of this happening"? I lose the connection every time I go through a nether portal, but this is the only scenario for me.
On my laptop I only run the minecraft client and skype for multiplayer communication purposes. The CPU usually is not at 100% when playing minecraft. However, if I lose the connection (e.g. after going through a nether portal) and I try to reconnect to my server without restarting the client, one out of two CPU cores goes to 100%.
The server network compression threshold is 256, this should be the default value.
Andrew Clarke: The server and the client are in the same network (local area network), connected by a switch. Both computers are in the same room - so for me there is no internet provider involved. However, I still get the error. And as I said, my friend who is connected to my server via the internet, does not experience the problem with the lost connection
For me this issue also started when switching to version 1.8. I get this error whenever I go through a nether portal. Instead of the "Downloading Terrain" message I get the "Connection Lost: Internal Exception: io.netty.handler.timeout.ReadTimeoutException" error message. The server and the client are in the same network connected by a switch (I am the server admin), so there should be no problem with the network connection. Even more interesting is the fact, that a friend of mine who is connected to my server over the internet, does not experience this problem.
Some other observations: After starting the minecraft client, I can connect to the server without any problems. However, if I disconnect from the server (on purpose, e.g. when I go AFK) and want to reconnect, I get the above mentioned error message. I have to restart my minecraft client in order to connect to the server.
Pierre Waldén, thanks for your detailed comment! I just did some testing again:
I tried giving minecraft (client) less memory. Default value set by the launcher was 1GB and I tried 512MB and 256MB. Result was the same - when I go through the nether portal, I get the timeout error.
RAM on server: My server has 12 GB of RAM - of those during normal operation approx 3-4 GB are used. The minecraft server is allowed to use up to 4 GB of RAM, but usually only uses a few 100 MB. At no time the server uses space on the hard drive as RAM.
RAM on client: My client has 4 GB of RAM. When playing minecraft, approx 1.5 GB are used and also at no time space on the hard drive is used as RAM
As I already stated, the problem does not occur when playing under windows 8. I just tried again and I can go through the nether portal without any problem. The nether appears almost immediately.
I forced a crash (using F3+C) when playing under linux (debian wheezy) and attached the crash report. I didn't find anything that immediately caught my attention. However, I also don't really know what to look for.
I didn't find the java switch which forces the server to log a full garbage collection. However, since the timeout problem does not happen when I play in windows 8 (and my friend, who plays on a Macbook with MacOS, also does not experience the timeout problem), I would say that the server is okay. Should I still force the server to log a full garbage collection? If yes, what is the right java switch?
And how do I run minecraft in a debug environment? I searched for a debug mode, but only got the mode in which the world consists of every type of block in every possible mode. But this sure is not the kind of debug mode I am looking for?