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Posted to server-user@james.apache.org by Hillel Bilman <hb...@ecommunicate.biz> on 2008/08/21 06:07:54 UTC

James uses up almost all the memory any suggestions

Hi,

 

We are using james-2.3.1 on Linux 64 bit Redhat with 8GB of RAM.

 

Using free:

                                  total       used       free     shared
buffers     cached

Mem:       8174276    8129120      45156          0       2696      42560

      -/+ buffers/cache:    8083864      90412

Swap:     16386248    8255480    8130768

 

We stopped James and now there is 7856744 memory available.

This means the server starts to go slowly.

 

Using free:

                                  total       used       free     shared
buffers     cached

Mem:       8174276     374404    7799872          0       3500      53372

     -/+ buffers/cache:     317532    7856744

Swap:     16386248     915912   15470336

 

If one of our mailets throws an exception could that cause it?

 

Why does this happen?  How can we prevent it?

 

Thanks

 


Re: James uses up almost all the memory any suggestions

Posted by Stefano Bagnara <ap...@bago.org>.
Hillel Bilman ha scritto:
> Hi,
> 
>  
> 
> We are using james-2.3.1 on Linux 64 bit Redhat with 8GB of RAM.
> 
>  
> 
> Using free:
> 
>                                   total       used       free     shared
> buffers     cached
> 
> Mem:       8174276    8129120      45156          0       2696      42560
> 
>       -/+ buffers/cache:    8083864      90412
> 
> Swap:     16386248    8255480    8130768
> 
>  
> 
> We stopped James and now there is 7856744 memory available.
> 
> This means the server starts to go slowly.
> 
>  
> 
> Using free:
> 
>                                   total       used       free     shared
> buffers     cached
> 
> Mem:       8174276     374404    7799872          0       3500      53372
> 
>      -/+ buffers/cache:     317532    7856744
> 
> Swap:     16386248     915912   15470336
> 
>  
> 
> If one of our mailets throws an exception could that cause it?
> 
>  
> 
> Why does this happen?  How can we prevent it?

1st: memory consumption for a linux tool is not measured with "free". 
Free tells you the memory used by the operating system as a whole.
Please check the memory with "ps", first and tell us what you see.

2nd: it is the normal behaviour for linux to use all of the memory you 
have because it uses the free memory as a cache when it understand it is 
not used by programs.

3rd: a java program will never use 8GB unless you configured java to use 
so much memory. The default Xmx (maximum heap size) for a java program 
depends on the JVM and the platform but I guess it never is more than 
256MB, so if you didn't alter the Xmx manually it is impossible for 
james to use 8gb.

4th: whenever you set a larger -Xmx then java will be allowed to use 
more memory and in case it will need once the memory will be allocated 
by java and never returned to the OS.

5th: you can get an heap dump from the james jvm just before stopping it 
to understand what there is in the JVM memory ("jheap" if you are on a 
recent jvm).

I guess there's a lot for you to think and reply before I go on with 
more points.

Stefano

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