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From Edson Richter <edsonrich...@hotmail.com>
Subject Re: Help in diagnosing server unresponsiveness
Date Sun, 03 Feb 2013 04:40:03 GMT
Just occurred to me: Linux has one feature that Windows doesn't: the OOM 
killer. When happens, normally you get a message in log.

Have you checked that?

If not, there is a little introduction here: 
http://linuxdevcenter.com/pub/a/linux/2006/11/30/linux-out-of-memory.html?page=1

Also, I had some issues with OOM killer in virtual machines running over 
qemu (actually, the OOM was happening in the host machine, not in guest 
- then in guest, had no error message).


Regards,

Edson


Em 03/02/2013 02:07, Zoran Avtarovski escreveu:
> Thanks Miguel,
>
> This is what I also suspect, but I can't see any evidence. The server has
> gone 10 days under heavy loads without a glitch and then it will hang a
> couple of times in the next few days with no apparent rhyme or reason.
>
>
> Z.
>
>
>
>
>
>
>
> On 3/02/13 5:56 AM, "Miguel González Castaños"
> <miguel_3_gonzalez@yahoo.es> wrote:
>
>> On 01/02/2013 20:08, Christopher Schultz wrote:
>>> -----BEGIN PGP SIGNED MESSAGE-----
>>> Hash: SHA256
>>>
>>> Zoran,
>>>
>>> On 1/31/13 8:36 PM, Zoran Avtarovski wrote:
>>>> We have a application running on the latest Tomcat7 and we are
>>>> getting a server crash or becoming unresponsive. This occur every
>>>> few days at no fixed intervals or time of day and they certainly
>>>> don't correlate to any app function ­ at least not according to the
>>>> logs.
>>> Can you describe the "crash" in more detail? OOME? IF so, what kind
>>> (heap or PermGen)? Lock-up (deadlock, etc)? Actual JVM crash (produces
>>> a core dump or native stack dump)?
>> I would go in that direction too. Enable logs and core or stack dumps
>> and analyze them. Be sure you are not restarting Tomcat in your crontab
>> (i had a server which was restarted once a week and masked some memory
>> starvation).
>>
>> In my case I can tell you I had to end up disabling JaveMelody (it was
>> provoking some side effects in our webapp as not managing international
>> chars in the right way). If reports from Javamelody are not giving you
>> any clue, beware that Javamelody has its own memory overhead (not much
>> in your case but in my case it was around 200 Mb of heap in a 1 Gb
>> virtual server).
>>
>> I followed Chris directions, I got stack dumps after a server crash and
>> analyzed it with eclipse analyzer. I realized our programmer decided to
>> load too many objects in memory than the server could cope with. So no
>> memory leak but bad memory management was the root cause.
>>
>> Regards,
>>
>> Miguel
>>
>>
>>
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>
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>


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