Re: GC(JVM Heap usage) tool

[Paulwintech <pa...@gmail.com>]

Hi,

  I need to check how many threads are running and its memory utilization in
tomcat6, I used jstack command to get thread details - but not able to get
memory usage details.

  Recently i get free memory critical for the particular time from tomcat6
and automatically get resolve after some time.I am not able to troubleshoot
the exact issue causing free memory critical - So to troubleshoot and to
find the exact reason - i wanted to know how to check the number of threads
are currently running and its memory usage. 

   After knowing the exact thread - i can check why that particular thread
occupies more memory. If im wrong please let me know any other ways to check
the issue.

  
Thanks
Paulwintech


Paulwintech wrote:
> 
> Hi,
> 
>  Thank you... Since we are using commercial monitoring tool and we are
> compelled to use the same. After special request they have replied back to
> use JMX tool to monitor our JVM heap.
> 
>   Please let me know, If we have any other tools that can monitor
> preciously JVM heap and tell us what process OR what Job takes Garbage
> Collection high(Taking more memory)
> 
> Thanks
> Paulwintech
> 
> 
> 
> Cyrille Le Clerc-3 wrote:
>> 
>> Hello Paulwintech,
>> 
>> I suggest you to have a look at Hyperic. It is a very interesting tool
>> and
>> you can extend it quite easily with custom JMX MBeans.
>> 
>> Cyrille
>> --
>> Cyrille Le Clerc
>> cleclerc@xebia.fr
>> 
>> On Mon, Feb 8, 2010 at 2:01 PM, Leon Rosenberg <
>> rosenberg.leon@googlemail.com> wrote:
>> 
>>> Hi,
>>>
>>> if you mean this kind of monitoring:
>>>
>>>
>>> http://moskito.anotheria.net/moskitodemo/mui/mskShowProducersByCategory?pCategory=memory
>>>
>>> than all you need is here:
>>>
>>> http://infra.anotheria.net/confluence/display/MSK/HowTo+Embed+Moskito+WebUI+In+Your+Application
>>>
>>> regards
>>> Leon
>>>
>>> On Mon, Feb 8, 2010 at 6:07 AM, Paulwintech <pa...@gmail.com>
>>> wrote:
>>> >
>>> > Hello All,
>>> >
>>> >    I need a java tool that can monitor my JVM heap usage, Since
>>> > intermediately i get GC free memory issue. Except JVM meter - Any
>>> other
>>> java
>>> > tools that will help me to troubleshoot my intermediate issue.
>>> >
>>> >
>>> > Thanks
>>> > Paulwintech
>>> > --
>>> > View this message in context:
>>> http://old.nabble.com/GC%28JVM-Heap-usage%29-tool-tp27495361p27495361.html
>>> > Sent from the Tomcat - User mailing list archive at Nabble.com.
>>> >
>>> >
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>>> >
>>> >
>>>
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>>>
>> 
>> 
> 
> 

-- 
View this message in context: http://old.nabble.com/GC%28JVM-Heap-usage%29-tool-tp27495361p27741009.html
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Re: GC(JVM Heap usage) tool

[Peter Crowther <pe...@melandra.com>]

On 1 March 2010 08:30, Paulwintech <pa...@gmail.com> wrote:
>  I need to check how many threads are running and its memory utilization in
> tomcat6, I used jstack command to get thread details - but not able to get
> memory usage details.
>
>  Recently i get free memory critical for the particular time from tomcat6
> and automatically get resolve after some time.I am not able to troubleshoot
> the exact issue causing free memory critical - So to troubleshoot and to
> find the exact reason - i wanted to know how to check the number of threads
> are currently running and its memory usage.
>
>   After knowing the exact thread - i can check why that particular thread
> occupies more memory. If im wrong please let me know any other ways to check
> the issue.

Much of the memory use is not thread-specific.  For example, Session
objects that are held for sessions that don't currently have a request
are not associated with any thread.  So I think you will have problems
checking why particular threads occupy more memory.

Also... how do you know your monitoring system isn't giving false
alarms?  A garbage collector should only run when it needs to - when
the JVM doesn't have enough free memory to satisfy the memory it
expects to use before the GC completes.  So I would expect free memory
to decrease to a very low amount, then the GC will run and free memory
will increase again.  Are you sure you understand what your monitoring
system is telling you, and once you know you understand it are you
sure you want to respond to that particular alert?

- Peter

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