java.net.ConnectException thrown

Trustin Lee (이희승) trustin at gmail.com
Thu Sep 17 22:36:17 EDT 2009


Sorry about the misleading post.  I was merely answering Mike's questions.

I have not experienced such a problem so far in Linux.  I am using
Fedora at the moment but I also use RHEL for performance tests.

Does the connection attempt succeed when you retry or fail forever once refused?

If all subsequent connection attempts are refused, it means the server
has been terminated for some reason.  Otherwise, it's a temporary
problem related with your operating system.

I'd like to investigate this problem further if there's a way to
reproduce the problem reliably.  Could you post a simple client-server
test application so that I can run it by myself? A simple modification
of the official examples would be perfect.

Thanks

— Trustin Lee, http://gleamynode.net/

On Fri, Sep 18, 2009 at 10:21 AM, J. Mi <jmi258 at gmail.com> wrote:
> Trustin,
>
> I already tried that. I tried to increase 'nofile' to 90000 both in
> /etc/security/limits.conf (and restart my Centos in VMware) and on the fly
> for a perticular termal session by 'ulimit -n 90000' command. None of them
> work for me.
>
> The exception I got was "java.net.ConnectException: Connection refused: no
> further information..", not "Too many open files..." althouth I seem to hear
> that file descriptors, connections and thread might share this same limit.
>
> This problem blocked me for days. And it doesn't seem to be the limit on
> http server side because I tried to use the same Netty http client to hit
> differnt server and had the same problem.
>
> Thanks for your help. Appreciated it.
>
> Jason
>
> On Thu, Sep 17, 2009 at 5:06 PM, Trustin Lee (이희승) <trustin at gmail.com>
> wrote:
>>
>> I hope this post answers the first question.
>>
>> http://gleamynode.net/articles/1557/
>>
>> I'm not sure about the other questions though. :)
>>
>> — Trustin Lee, http://gleamynode.net/
>>
>>
>>
>> On Fri, Sep 18, 2009 at 2:37 AM, Michael McGrady
>> <mmcgrady at topiatechnology.com> wrote:
>> > What is the impact of changing these settings?  Why is the default low
>> > instead of hight?  And, any other questions I should be asking before
>> > changing this configuration?
>> > MIke
>> > On Sep 17, 2009, at 10:34 AM, J. Mi wrote:
>> >
>> > H Thomas,
>> >
>> > Thanks for the lead. To be able to have more connections before seeing
>> > "java.net.ConnectException: Connection refused...", which configuration
>> > I
>> > need to change in /etc/security/limits.conf? I added
>> > * soft nofile 20000
>> > * hard nofile 20000
>> >
>> > and first time just tried to re-login, the new limit didn't work for me
>> > for
>> > more connections. I then tried to restart my VMware. It still didn't
>> > work
>> > for me
>> >
>> > Does 'nofile' (max number of open files) have anything to do with socket
>> > connections?
>> >
>> > Appreciate if you or anyone else can guide me more on this.
>> > btw, if any of you know any equivalent OS settings on Windows, i'll try
>> > that
>> > as well.
>> >
>> > Jason
>> >
>> >
>> > On Wed, Sep 16, 2009 at 3:38 PM, Thomas Bocek <bocek at ifi.uzh.ch> wrote:
>> >>
>> >> Hi J.,
>> >>
>> >> This might be a limitation of the OS. If you are using for example
>> >> Linux, then you can only open about 1000 connections before seeing "too
>> >> many open files in system" error messages. You can adjust the value in
>> >> /etc/security/limits.conf
>> >>
>> >> Thomas
>> >>
>> >> J. Mi wrote:
>> >> > All,
>> >> >
>> >> > I get following exception pretty consistently when trying to
>> >> > concurrently
>> >> > connect about 800 connections.
>> >> >
>> >> > Any idea? Is this something out of Netty's control? If so, is there
>> >> > some
>> >> > configuration I could do to JVM or operating system to increase
>> >> > resource
>> >> > capacity?
>> >> >
>> >> > Thanks,
>> >> > Jason
>> >> >
>> >> > java.net.ConnectException: Connection refused: no further information
>> >> >         at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
>> >> >         at sun.nio.ch.SocketChannelImpl.finishConnect(Unknown Source)
>> >> >         at
>> >> >
>> >> >
>> >> > org.jboss.netty.channel.socket.nio.NioClientSocketPipelineSink$Boss.connect(NioClientSocketPipelineSink.java:381)
>> >> >         at
>> >> >
>> >> >
>> >> > org.jboss.netty.channel.socket.nio.NioClientSocketPipelineSink$Boss.processSelectedKeys(NioClientSocketPipelineSink.java:351)
>> >> >         at
>> >> >
>> >> >
>> >> > org.jboss.netty.channel.socket.nio.NioClientSocketPipelineSink$Boss.run(NioClientSocketPipelineSink.java:273)
>> >> >         at
>> >> >
>> >> >
>> >> > org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:113)
>> >> >         at
>> >> >
>> >> >
>> >> > org.jboss.netty.util.internal.IoWorkerRunnable.run(IoWorkerRunnable.java:53)
>> >> >         at
>> >> > java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown
>> >> > Source)
>> >> >         at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown
>> >> > Source)
>> >> >         at java.lang.Thread.run(Unknown Source)
>> >> >
>> >> >
>> >> >
>> >> >
>> >> > ------------------------------------------------------------------------
>> >> >
>> >> > _______________________________________________
>> >> > netty-dev mailing list
>> >> > netty-dev at lists.jboss.org
>> >> > https://lists.jboss.org/mailman/listinfo/netty-dev
>> >> _______________________________________________
>> >> netty-dev mailing list
>> >> netty-dev at lists.jboss.org
>> >> https://lists.jboss.org/mailman/listinfo/netty-dev
>> >
>> > _______________________________________________
>> > netty-dev mailing list
>> > netty-dev at lists.jboss.org
>> > https://lists.jboss.org/mailman/listinfo/netty-dev
>> >
>> > Mike McGrady
>> > Principal Investigator AF081-028 AFRL SBIR
>> > Senior Engineer
>> > Topia Technology, Inc
>> > 1.253.720.3365
>> > mmcgrady at topiatechnology.com
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> > _______________________________________________
>> > netty-dev mailing list
>> > netty-dev at lists.jboss.org
>> > https://lists.jboss.org/mailman/listinfo/netty-dev
>> >
>> >
>>
>> _______________________________________________
>> netty-dev mailing list
>> netty-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/netty-dev
>
>
> _______________________________________________
> netty-dev mailing list
> netty-dev at lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/netty-dev
>
>



More information about the netty-dev mailing list