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    posted a message on HOW-TO: Run a server on Amazon EC2
    More updates...

    It can definitely handle 2 people. Easily.
    Three people... it seems to depend on who joined. I've had some very good sessions with three people on the server.
    Yet just recently, three people started to choke the little micro server.
    I was setting the cpulimit between 30-50%. Seems that's around the point where the amazon throttle kicks in.

    Anyways, might still be too early to tell. But I can pretty much guarantee it works with 2 people.
    Posted in: Server Support and Administration
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    posted a message on /save-all
    Keep in mind,

    I believe the bug still exists: If you /save-off, save-all no longer does anything. I found this out painfully.
    /save-on has to be on for save-all to do anything.

    Also, most people who do backups just have a simple backup script to zip (or tar or wtever) either by time or whenever they call the command.
    Posted in: Server Support and Administration
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    posted a message on HOW-TO: Run a server on Amazon EC2
    Hello,

    I FOUND A SOLUTION! (FOR THE MICRO INSTANCE USERS)
    (assuming you chose the cheaper linux instance, which you SHOULD)

    If you want to run a small MC server on a EC2 MICRO instance, you are going to have to limit the cpu usage of the java process. Install cpulimit (google is your friend). It is a very simple utility that allows you to limit a processes CPU usage by PERCENTAGE.

    http://cpulimit.sourceforge.net/
    (I had to install gcc too before "make" worked for cpulimit)
    (I also installed svn so I could just easily get it with:
    "svn checkout https://cpulimit.svn.sourceforge.net/sv ... imit/trunk cpulimit")

    Example: "sudo ./cpulimit -e java -l 25 -v -z"
    This runs the command as root (which is supposedly better?)
    Looks for the java process (there is an option for PID if you need it)
    -l 25 means limit to 25%
    -v is verbose so you can see it in action
    -z is "lazy" meaning it quits when the process closes

    What this does is essentially make you the cpu throttler instead of horrible amazon. If you allow MC to run free, it spikes up for a short bit and amazon throttles it back, you hit 99% usage for up to 30s or a minute even, clients get dropped, server freezes, its bad.

    WITH cpulimit in place, the server occasionally has a small bit of lag. Small meaning lasts about 5-10 seconds at WORST, and does not cause disconnects. It is now playable, feasible, reasonable, usable, manageable, and no longer frustrating! Best of all, its insanely CHEAP. (even more so if you're a first time user)

    I run several mods, with biome + craftbukkit. I was playing with 3 people on the server at once.

    Hope this helps someone... If it does, please reply with your results and/or questions.

    (Keep in mind, its probably best to run your MC server and the cpulimit utility in screens. I assume if you have this problem and you've gotten to this point, you know what a screen is.)
    Posted in: Server Support and Administration
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    posted a message on HOW-TO: Run a server on Amazon EC2
    Quote from Marzuk »
    As far as I can tell running a Minecraft Server on an EC2 Micro is not viable, or at least volitile. I tried with a friend for a while and we figured it was a problem with his NIC (previously noted in the forums). I also guessed that the poor I/O characteristics of the Micro coupled with the heavy reads of thousands of small files was less than optimal.

    We did not do much until 1.3, and I wanted to revisit it because of the new save format. Still having some issues I continued to tweak and even set up a ramdrive to take care of any I/O issues. I figured "Hey, if its an I/O problem this should be awesome!". Max I need to be able to host 3 to 5 players, so I was not too worried about having enough ram to allocate for the server.

    After still having a problem I ran into some interesting things:

    http://gregsramblings.com/2011/02/07/am ... cpu-steal/

    http://huanliu.wordpress.com/2010/06/14 ... pute-unit/

    There are more examples, but essentially the server appears to run fine until you touch the CPU just a bit too much or often, and top shows 90%st + and java lists at 99% cpu etc. During this time you really can't do anything / break blocks etc. Given a short period of time, it goes back to 0.0%st and you can play again. Once I noticed that the issue was CPU related, at that point any time I noticed a disturbance in the game I could look over and verify that was the issue with top.

    I noticed this happening when chunks were being generated (especially obvious on a new map) and when day was transitioning to night. I also noted it happening at random, when I could not really connect it to a specific event. Unfortunately I think it happens just frequently enough to make it a frustrating experience to attempt to play.


    Hey have you figured out anything?
    I'm also experiencing the same thing... I can't relate it to anything I do meaning it seems it happens at random. Even when I'm just a single player on the server.
    It's frustrating enough so that me and 2 friends figure its not worth it to try playing on it.
    Are you playing on a vanilla server?

    Thanks for the interesting links though... Have you tried any CPU limiting on your own side? Is that even possible/feasible?

    Thanks!
    Posted in: Server Support and Administration
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