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#1

syonxwf
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Posted 15 December 2011 - 04:33 AM

I am constantly getting spammed on the server with "Did the system time change, or is the ser
ver overloaded?" But I have no idea why.  
Server specs:

4 dual core 2.8ghz prods
12gb ddr2 ram
4 72gb 15k scsi's
22mb down / 5mb up lan connection

My system utilization sits around 15% ram usage, 10% cpu usage with 8-10 people on, and they have noticed that the server is lagging but I just am not sure why.

My java version is the newest stable version, 6 .29 I believe.
Im using bukkit (1597), with multiple pluggins, including a sql server for logblock, but because my servers resource utilization is so low I wouldnt think that would be an issue.
Anyone have any ideas?

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#2

webrosc
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Posted 15 December 2011 - 04:51 AM

how much ram is allocated to the server?

#3

syonxwf
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Posted 15 December 2011 - 05:07 AM

View Postwebrosc, on 15 December 2011 - 04:51 AM, said:

how much ram is allocated to the server?

In the starter file I've got it set to 1g, I've tried to change that to 2g but then it fails to start, I tried to allocate more by taking the xnx??1g (can't remember exactly what it says, on my phone) and repeated it so that its -xnx??1g -xnx??1g, but didn't notice a difference (though I could be doing it wrong or maybe I should allocate more?)

Sorry for the shitty grammar, its really hard to type this all on my phone lol

#4

webrosc
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Posted 15 December 2011 - 05:18 AM

its xmx

java.exe -Xincgc -Xmx2G -jar craftbukkit.jar (this is what i use)

you'll need 64bit windows and java to allocate more than 1.4?gig

it won't hurt to allocate more as you have 12 in the system

your net speed should be ok for around 15 people i think

#5

syonxwf
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Posted 15 December 2011 - 05:37 AM

View Postwebrosc, on 15 December 2011 - 05:18 AM, said:

its xmx

java.exe -Xincgc -Xmx2G -jar craftbukkit.jar (this is what i use)

you'll need 64bit windows and java to allocate more than 1.4?gig

it won't hurt to allocate more as you have 12 in the system

your net speed should be ok for around 15 people i think


I may reinstall with 64the bit then in order to utilize that, thank you.

#6

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Posted 15 December 2011 - 07:04 AM

Also set the java priority to HIGH in task manager could help?

#7

syonxwf
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Posted 15 December 2011 - 07:43 PM

View Postmishrathium, on 15 December 2011 - 07:04 AM, said:

Also set the java priority to HIGH in task manager could help?

I have been setting the java priority to realtime (the server functions no other purpose than minecraft, so I want it to solely focus on it).

One of my plugins allows me to look at Free memory, total memory, and max memory, and I ran it while the server was not spamming me with the warning, I got:

11:32 AM [INFO] Free memory: 86.7MB
11:32 AM [INFO] Total memory: 653.9MB
11:32 AM [INFO] Max memory: 1011.3MB '

Weird I thought, low on free memory but the total memory is no where near max.  Ran it again:

11:32 AM [INFO] Free memory: 73.1MB
11:32 AM [INFO] Total memory: 653.9MB
11:32 AM [INFO] Max memory: 1011.3MB

So it looks like a memory leak now.  Soon as I ran it this time though, server started spamming warnings, and then I ran memory again, assuming it would be at or close to 0 free:

11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [INFO] Free memory: 362.7MB
11:32 AM [INFO] Total memory: 653.9MB
11:32 AM [INFO] Max memory: 1011.3MB
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?
11:32 AM [WARNING] Can't keep up! Did the system time change, or is the server overloaded?

Now I am utterly confused...Nothing changed between the two times (same amount of players, no severe or java errors)

I am going to reinstall windows tonight with x64, and I will allocate 10gb of ram to the game and see if that fixes it.

#8

Lord_Ralex
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Posted 15 December 2011 - 08:23 PM

View Postsyonxwf, on 15 December 2011 - 07:43 PM, said:

I have been setting the java priority to realtime (the server functions no other purpose than minecraft, so I want it to solely focus on it).

One of my plugins allows me to look at Free memory, total memory, and max memory, and I ran it while the server was not spamming me with the warning, I got:

11:32 AM [INFO] Free memory: 86.7MB
11:32 AM [INFO] Total memory: 653.9MB
11:32 AM [INFO] Max memory: 1011.3MB '

Weird I thought, low on free memory but the total memory is no where near max.  

It is that Java was allocated so much memory, but will dynamically increase or decrease its total memory, but will not go past the max memory.

The java flag -Xms will always dedicate that much memory to the server, regardless of whether it needs it. Just using -Xmx means that it will use up to that much, but will not allocate it all from the beginning.

When I run my server, i use java -Xmx1024M -Xms1024M -jar craftbukkit_1597.jar
That creates my JVM with 1 GB of memory and allocates it all so if I was to see the total memory, it would be very close to the max

You can see a similar effect if you run minecraft the same way, and press f3 to watch the performance.

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#9

Defakto227

Posted 16 December 2011 - 06:46 AM

Do not set java to Real Time priority.

This affects your entire computer.  Everything.  Real Time priority means java will take precedence over, virtually, all other functionality going on, on the server.  Disk access that requires CPU usage, Keyboard, and Bus access (everything attaches to a bus to move data around) are just a few examples.  

A thread running at Real Time CANNOT be interrupted by the system. It will completly, utterly, and totally bring down system performance to give java real time access.