I am new to jboss server level configuration. Our application is hosted in windows server and running through power shell. Once in a day power shell got hanged and we are restarting the jboss server.
Heap memory
-Xms1024m
-Xmx8192m
32 GB RAM
Please let me know if you required any other configuration to identify the issue.
Help us to identify the root cause.
One of the reason might be clicking inside Windows Power Shell, makes the power shell to wait and the cascade effect makes all the threads wait and finally results in server hung.
Reason:
Clicking inside the windows power shell, knowingly or unknowingly it stops the output in the console and also the output to the log file. This could hold the thread which tries to write the log and hence we have other threads waiting.
Solution:
Temporary:
Once any key is pressed on the windows power shell,
it releases the console output and log and hence all the threads are released.
Permanent:
Uncheck the properties QuickEdit Mode and\or Insert in the windows power shell, this will not have any impact on our application, as we don’t need this feature enabled for our window power shell. Please read this blog.
Check this link to tune the perfomance of JBoss AS 7
Performance tuning
Related
I'm experiencing this weird problem that the JVM hangs forever very frequently.
I first observed the problem when my Java IDEs frequently hang the entire system GUI. IntelliJ IDEA hangs on indexing almost every single time upon start. Sometimes it proceeds to resolving dependency but always hangs in the end. When this happens, I can type in gnome-terminal, but the commands can't seem to be executed. I can't launch new applications with Alt-F2 or anything alike.
I had to switch to a text console and "killall -9 java" to kill the IDEA process and get control back. "kill -3 java" won't work. The log file contains nothing related, the thread dump is empty. Once the IDE hung, jstack cannot be attached to the process. "jstack -l pid" also hangs. "jstack -F pid" can't attach to the process. Visualvm hangs as well.
The CPU usage by the Java process is 0% and there is no I/O going on.
I've observed the same behavior when using Eclipse. Sometimes it hangs on start up, sometimes upon saving and sometimes upon running a Java application.
Maven / sbt builds executed within text-only ttys cause the same kind of hang, so I guess it's not a window manager / desktop environment / display driver problem.
I highly suspect it's a file system or I/O issue but I have no clue how to debug that. I've tried fsck with no luck, and my system works perfectly fine when not running java programs.
Things I've ruled out:
Permission issues: running IntelliJ with sudo doesn't help, hangs 100% of the time.
Display driver: I've tried both the Nvidia proprietary driver and nouveau, the open source one. Doesn't help.
Window manager / desktop environment: I use Cinnamon, but I've tried running IntelliJ under Unity. Doesn't help.
Java version: I've tried both Oracle Java 7 and Oracle Java 8. I'll probably try OpenJDK but I doubt it would work.
IntelliJ version: I've tried IntelliJ 13 through 14.1. All exhibited the same behavior.
Limited memory: I have 16G RAM with 16G swap space, so memory should not be a limiting factor.
Kernel log doesn't look suspicious. I can't get any kind of log remotely indicating what went wrong.
Any idea?
UPDATE (2015/04/29): The problem seems to have fixed itself after I accidentally kicked the power cable and cold restarted the computer... Still a mystery but IntelliJ is usable as of now.
Some things to check
- The Java IDEs run best with a lot of ram. I usually ask for at least
8G of memory for my dev workstation.
- Make sure you have a stable version of everything, look for known working versions/configurations on Ubuntu
- You have to manually allocate memory in IntelliJ IDEA versions < 14. For example: How to increase IDE memory limit in IntelliJ IDEA on Mac?
- Besides system logs, run tools like top and see what's happening in terms for cpu and ram when running the IDE
I had similar problems a while ago but with Eclipse. The problem was that there was no swap place at all ;) - obviously it should not be a problem with 16GB of RAM.
Could You post JVM arguments for Intellij? And also I have an idea to create another Intellij installation (eg. go back to 14 version) and see if there is similar problem (also compare JVMs settings between these two).
Edit
Ok so try:
use different JRE/JDK. If the problem disappears it will tell us more.
You are on linux so it makes it easy to monitor several things - you said that there is no CPU utilization or hard I/O. But how do you know that? Maybe it will be informative to have some statistics gathered - eg.jstat for JVM itself or for system information (You think that is I/O problem) try:
iostat -hm -p sda 1
Which will print I/O statistics for sda (if you have different discs change device parameter) in 1sec loops (can be also changed). Start this with system and dump output to the file - maybe there is some kind of 'disaster' happening before JVM hangs. Note: iostat sometimes is not available on system itself (on my Linux Mint is not) - install then package sysstat and the command will be available.
Seem to have fixed after a cold restart from an accidental power loss.. Weirdest problem I have ever seen.
I have a Wildfly-8.0.0.Final server running in standalone mode on a Windows machine.
To configure the JVM memory allocation I edited the $JBOSS_HOME\bin\standalone.conf.bat, adding the following:
set "JAVA_OPTS=-Xms512M -Xmx2048M -XX:MaxPermSize=512M"
In the console administration > Runtime > Platform > JVM I noticed that the memory is ok (after some time, it's being released), but the number of threads increases at each client connection.
For the other server configuration I kept the default values.
At the server startup the number of threads is: live 60, daemon 20, but after a few hours I found live 400, daemon 360. I'm not an expert, but this seems to be an error. Is it true? How can I limit the number of threads?
I noticed in console administration Profile > Core > Threads both "Thread Pools" and "Thread Factories" are empty.
With the information you provide it's nearly impossible to know what's going on.
When you have problems with threads what you should do is profile your application. You could have a thread pool misconfigured causing troubles ( from a Quartz to a database one) which you have no idea about.
IDE Approach
With modern IDEs you should be able to see all the running threads in debug mode. If you can't find a way to start in debug mode your application from the IDE, you could try to use remote debugging.
Thread dump
The JDK has a very nice took called jstack that you can use to get a snapshot of the stack trace for all the threads in a Java application.
Professional Profiler
You can try either JDK's VisualVM or one of the many payed profiles out there. The profiler could give you more information about the threads (when they are created, when they die, how their state changes...)
I guess you have to set the follwing parameter in the start script:
-Dorg.jboss.server.bootstrap.maxThreads
We have trouble with Tomcat 5.5 which stops at night on our production servers (Linux CentOS 4.8) and we have no idea why it stops...
There is no Tomcat's log in catalina.out or any application's log.
We tried different things to find why the server stops:
configure Tomcat to be able to generate a core dump
instrument System.exit() method with javassist to find if the method was called
add a shutdown hook to the JVM (with Runtime.getRuntime().addShutdownHook())
None of them worked, we have no core dump, the Exit method and the shutdown hook are not called.
My conclusions are:
The VM is not terminated properly but crash without any log.
Any idea or log to read to find why Tomcat stops?
1) Make sure you know where stderr is redirected and check if anything got printed there.
2) Check the memory limits on Tomcat and how much free memory does the system have. Review the Linux system logs under /var/log to see if anything suspicious happened during the time. For example, kernel can randomly kill a process (almost) without a trace if the system is running low on memory.
We've ran 5.5 in production for years and never had any unexplained shutdowns, FWIW.
This worked for me.
As suggested here in other answers checked system logs in /var/log/messages but permission denied for me. So, I used dmesg command instead and got this in the logs
"Out of memory: Kill process 14606 (java) score 106 or sacrifice child".
In the output I also noticed Swap Memory free 0 K. Ran top command to confirm the same. So, somehow there was a high memory usage which caused the OS to kill my tomcat process.
After spending hours finally got the reason.
ps -ef | grep tomcat showed that there were several tomcat processes running for the same application. It seems that, earlier tomcat shutdowns might not have been completed successfully and due to some reason the processes were not killed even after the shutdown, which was causing the high memory usage.
So, killed all running tomcat processes using kill. SWAP memory got freed.
Started tomcat again, worked fine. :)
Tomcat 7 has an option inside catalina to prevent the System.exit class call or something similar: http://ci.apache.org/projects/tomcat/tomcat7/docs/security-manager-howto.html .
Maybe there's a similar option for the 5.5 version. Try the documentation.
There are options to redirect the output to the same console that you use to start Tomcat. This information is redirected to logs when you execute on Unix based systems, on Windows, it remains with the console if not redirected.
Most probably there is a stack-overflow exception. This is typical behavior of Tomcat when it happens. For example, you're trying to serialize to JSON or XML beans with cyclic dependencies (but without handling of the cycles).
Everytime I had this issue (several times) it always has been this one. All other stops are usually logged properly (like OutOfMemory etc).
This type of stops leaves no trace anywhere.
I'm having problems with jetty crashing intermittently, I'm using Jetty 6.1.24.
I'm running a neo4j Spring MVC webapp, Jetty will stay running for approx 1 hour and then I have to restart Jetty. It is running on small amazon ec2 instance, debian with 1.7gb of RAM.
I start Jetty using java -Xmx900m -server -jar start.jar
I am connecting to the server using putty, when Jetty crashes the putty session disconnects, I cannot see what error caused it to crash.
I would like to be able to see if it is an error generated by Spring, I'm not sure how to log the output from the spring app with Jetty. Or if it is Jetty or a memory issue, what would be the best way to monitor Jetty? I cannot recreate this on my local machine running windows. What do you think would be the best way to approach this? Thanks
This isn't really a programmer question; perhaps it'll be moved over to ServerFault.
You didn't specifically state which operating system you're using, but I'm hazarding a guess at some Linux distribution. You have two options of figuring out what's wrong:
Start your session in screen. Screen will live for as long as the actual machine is powered on, until you reboot the operating system (or you exit screen).
you start screen like this
screen
and you get a new prompt where you can start your program (cd foo, jetty, etc). When you're happy and you just need to go somewhere, you can disconnect the screen by hitting CTRL+A and then CTRL+D. you'll drop back to the place you were before you invoked screen.
To get back to seeing the screen you type screen -R which means to resume an existing screen. you should see jetty again.
The nice thing is that if you lose connection (or you close putty by accident or whatever) then you can use screen -list to get a list of running screens, and then forcibly detach them -D and reattach them to the current putty -R, no harm done!
Use nohup. Nohup more or less detaches the process you're running from the console, so none of its output comes to the terminal. You start your program in the normal fashion, but you add the word nohup to your command.
For example:
nohup ls -l &
After ls -l is complete, your output is stored in nohup.out.
When you say crash do you mean the JVM segfaults and disappears? If that's the case I'd check and make sure you aren't exhausting the machine's available memory. Java on linux will crash when the system memory gets so low the JVM cannot allocate up to its maximum memory. For example, you've set the max JVM memory to 500MB of which it's using 250MB at the moment. However, the Linux OS only has 128MB available. This produces unstable results and the JVM will segfault.
On windows the JVM is more well behaved in this scenario and throws OutOfMemoryError when the system is running low on memory.
Validate how much system memory is available around the time of your crashes.
Verify if other processes on your box are eating up a lot of memory. Turn off anything that could be competing with the JVM.
Run jconsole and connect it to your JVM. That will tell you how memory is being used in your JVM process and give you a history to look back through when it does crash.
Eliminate any native code you might be loading into the JVM when doing this type of testing.
I believe Jetty has some native code to do high volume request processing. Make sure that's not being used. You want to isolate the crashes to Java and NOT some strange native lib. If you take out the native stuff and find it works then you have your answer as to what's causing it. If it continues to crash then it very well could be what I'm describing.
You can force the JVM to allocate all the memory at startup with -Xms900m that can make sure the JVM doesn't fight with other processes for memory. Once it has the full Xmx amount allocated it won't crash. Not a solution, but you can easily test it this way.
When you start java, redirect both outputs (stdout and stderr) to a file:
Using Bash:
java -Xmx900m -server -jar start.jar > stdout.txt 2> stderr.txt
After the crash, inspect those files.
If the crash is due to a signal (like SEGV=segmentation fault), there should be a file dump by the JVM at the location you've started java. For Sun VM (hotspot), it's something like hs_err_pid12121.log (here 12121 is the process ID).
Putty disconnecting STRONGLY hints that the server is running out of memory and starts shutting down processes left and right. It is probably your jetty instance growing too big.
The easiest thing to do now, is adding 1-2 Gb more swap space and do it again. Also note that you can use the jvisualvm to attach to the jetty instance to get runtime information directly.
I've been running Tomcat 5.5 with Java 1.4 for a while now with a huge webapp. Most of the time it runs fine, but sometimes it will just hang, with no exception generated, and no apparant way of getting it to run again other than re-starting Tomcat. The tomcat instance is allowed a gigabyte of memory on the heap, but rarely exceeds 300 MB. Has anyone else run into this issue, and is there a solution for it?
For clarification: I determined how much memory it is using via Task Manager and via Eclipse (I've also tried running it outside of Eclipse, but get the same problem eventually, though it takes a little longer). With Eclipse, I look at the memory allocated via its little (optional) memory pane and the amount allocated to javaw.exe via the task manager. I use the sysdeo? tomcat plugin for Eclipse.
For any jvm process, force a thread dump. In windows, this can be done with CTRL-BREAK, I believe, in the console window.
In *nix, it is almost always "kill -3 jvm-pid".
This may show if you have threads waiting on db connection pool/thread pool, etc.
Another thing to check out is how many connections you have currently to the JVM -- either use NETSTAT or SysInternals utility such as tcpconn/tcpview (google it).
Also, try to run with the verbose:gc JVM flag. For Sun's JVM, run like "java -verbose:gc". This will show your garbage collections. If it is collecting a lot (FULL COLLECTIONS, expecially) then you probably have a memory leak. The full collections are costly, especially on large heaps like that.
How are you determining that only 300mb are being used?
It sounds like you're hitting a deadlock.
If you can reproduce it in a dev environment then try attaching a debugger once it's happened. Take a look at your threads and see if you have any deadlocks.
If you can't get a debugger to attach you should be able to generate a thread dump, as Dustin pointed out.
Try increasing the logging sensitivity for the Tomcat application server.
http://tomcat.apache.org/tomcat-5.5-doc/logging.html
You can increase the sensitivity to FINEST or ALL for most of them for a few days and see if that helps you catch anything.
I agree with creating multiple thread dumps and viewing them though this: Thread Dump Analyzer