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Old 10-11-2011, 14:43
rventura rventura is offline
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Default Server off-line for 2 minutes

Hi,

I'm using java-monitor to know when my server goes down, but sometimes I receive an email message that it has gone off-line and after 2 minutes it's on-line again. It seems like my server has not been rebooted or the Tomcat server restarted, as I can't find any log about it, and I suspect it could be just a problem with the java-monitor server that is unable to connect to my server. Does anyone have the same problem?

Thank you,

rventura

Last edited by rventura; 10-11-2011 at 14:45.
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Old 11-11-2011, 09:03
kjkoster kjkoster is offline
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Dear rventura,

Is this with all of your JVMs or with one specific one? If it is with a specific one, is it in another data center as the others? How are these machines hosted?

I have seen machines that were hosted on ADSL lines at someone's house where the same thing would happen. In such situations it is useful it make the notification time-out 5 minutes instead of 2 minutes.

Kees Jan
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Old 11-11-2011, 10:12
rventura rventura is offline
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Dear kjkoster,

Thank you for you quick answer. Our server is a contracted online hosting server and we use it through Remote Desktop. We have installed only a single JVM and, obviously, ther server doesn't have a normal home ADSL line. We're gonna try to change the time-out to 5 minutes and see if it doesn't happen.

Thank you,

rventura
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Old 11-11-2011, 14:28
kjkoster kjkoster is offline
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Dear rventura,

Right, I was just checking you are not on ADSL. Changing the notification timeout will reduce the number of warnings, but not help you solve the actual problem. The missed samples usually have a reason.

Please have a look in the logs of your application server. You might find Java-monitor related stack traces in there.

I usually look up the threads graph (since it is nice and solid) and see if there are tiny vertical lines through it that show missed samples. Things I have seen in the past were late GC pauses of 60 seconds or more and network issues, like broken network adapters, bad cables or routing issues.

Broken network adapters usually result in large number of errors on the adapter. Your OS will report these somewhere. Since you mention remote desktop I assume you are on Windows, and I know nothing about Windows. It is there somewhere, I am sure.

On other machines I ran a traceroute every 5 mins for a week to a known working machine to see if there were intermittent router issues. There were in my case.

Kees Jan
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Old 11-11-2011, 15:51
rventura rventura is offline
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Dear kjkoster,

I have found the following error in the log files inside the folder "logs" of my Tomcat:

Nov 7, 2011 3:38:28 PM com.javamonitor.JavaMonitorCollector$CollectorDriv er run
SEVERE: This probe was hit by an unexpected exception: Connection reset
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream. java:168)
at java.io.BufferedInputStream.fill(BufferedInputStre am.java:218)
at java.io.BufferedInputStream.read1(BufferedInputStr eam.java:258)
at java.io.BufferedInputStream.read(BufferedInputStre am.java:317)
at sun.net.http://www.http.HttpClient.parseHTTP...lient.java:695)
at sun.net.http://www.http.HttpClient.parseHTTP...lient.java:640)
at sun.net.http://www.http.HttpClient.parseHTTP...lient.java:660)
at sun.net.http://www.protocol.http.HttpURLConn...tion.java:1195)
at com.javamonitor.Collector.push(Collector.java:334)
at com.javamonitor.Collector.push(Collector.java:140)
at com.javamonitor.JavaMonitorCollector$CollectorDriv er.run(JavaMonitorCollector.java:153)
at java.lang.Thread.run(Thread.java:662)

This error appears several times in the different files, does it give you information about what the problem could be?

Thank you

Robert Ventura
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Old 11-11-2011, 16:05
kjkoster kjkoster is offline
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Dear Robert,

This is a fairly generic 'something went wrong on the network' message. Unfortunately, it does not tell us anything we did not know already. Sorry. Thanks for looking it up, though.

Kees Jan
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