Server becomes unresponsive for unknown reason

[Alan Wolff]

Hi

Please provide us with more info such as JVM version and OS info

Here are some pointers which should help you:

You should observe a thread dump and establish if any threads are
executing a long-term blocking operation which causes the server to be
non-responsive

You should observe CPU usage. If it's high, you need to pinpoint which
thread is causing it and observe what that thread is doing and
furthermore solve the problem. If it's a GC thread, either allocate
more memory, check for memory leaks and fix them

You should check if the server is polling for messages, if the
messages reach the server (use a network monitoring tool) and if so at
which point these messages are not being processed (Add LoggingHandler
in the pipeline)

Profiling your application should help you with solving your problem

I'm sure there are lots of articles out there on troubleshooting Java
app servers, don't stop reading :-)

Best of luck
Alan

On Wed, Jun 2, 2010 at 8:45 PM, huni <safasofuoglu at gmail.com> wrote:
>
> Hello,
>
> I am running a busy server based on netty. Occasionally -like once a week-,
> I experience a lockdown on the server, which causes the server become
> unresponsive to clients. I have to kill and restart the server to make it
> continue its normal operation.
> I am logging exceptions, but logs dont show any evidence about this
> situation. I also have a memory dump of the process when the lockdown
> occured, but I don't know where to look for clues.
>
> Is it possible to be caused by a systematic attack? Like, some clients
> opening massive connections or sending massive data?
>
> Do you have any other ideas why something like this might occur?
>
> Thanks.
> --
> View this message in context: http://netty-forums-and-mailing-lists.685743.n2.nabble.com/Server-becomes-unresponsive-for-unknown-reason-tp5132023p5132023.html
> Sent from the Netty User Group mailing list archive at Nabble.com.
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