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From Gabe Wong <gabri...@ngasi.com>
Subject Re: Vmware and Tomcat 5.x & 6.x
Date Tue, 25 Sep 2007 02:42:13 GMT
Mitesh,
The most important thing with regards to the JVM, is available memory. 
Of extra importance in this case is the amount of memory (REAL/PHYSICAL)
allocated to the Virtual Environment (VMWare). That said, you also need 
to determine the Memory Heap usage of each of the JVM instances.
Sluggishness usually indicates a memory shortage. At that point SWAP 
consumption increases. As you would image disk swap would be much
slower than real memory. Besides sluggishness, SWAP usage may increase 
the chance of disk failure because essentially you are using a 100% of
resources.  In short compare the total Memory Heaps of all the JVMS to 
the total memory allocated to the Virtual Environment of the VMWare 
instance.


Mitesh Shah wrote:
> Thanks Chris for reply. Clarion is SAN, so all are data and OS partitions
> are on SAN.
>
> Whole server works fine but our application works using tomcat and I have
> installed around 20 instances of tomcats on one virtual machine (2.66GHz and
> 4GB RAM). On similar line, does JDK takes advantage of two CPU compared to
> one CPU?
>
> I can reconfigure Swap file on separate disks than OS disk and see if it
> performs better.
>
> Please let me know if above info helps in understanding issue better?
>
> Mitesh Shah
> Hosted Services Engineer
> -----Original Message-----
> From: Christopher Schultz [mailto:chris@christopherschultz.net] 
> Sent: Monday, September 24, 2007 6:01 PM
> To: Tomcat Users List
> Subject: Re: Vmware and Tomcat 5.x & 6.x
>
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> Mitesh,
>
> Mitesh Shah wrote:
>   
>> This is first ever deployment of our product on virtual environment and we
>> are facing lots of issues of slowness. There are too many variables to
>> monitor and looking for some path to follow. 
>>     
>
> Is the whole server slow, or do you notice that certain operations are slow?
>
>   
>> I was hoping to get some input as if anyone is aware of such issue of
>>     
> vmware
>   
>> and tomcat.
>>     
>
> AFAIK, there are no Tomcat-specific vmware issues. However, there could
> be some problems with the JVM in general that you might be coming
> across. For instance, if you are using a source of randomness that
> blocks when used through the virtual environment, that might cause a
> problem. Also, if you are using non-native disks (meaning a big file on
> the host OS that holds the entire filesystem for the VM), you may
> experience some slowdown, there.
>
> I'm not sure what Clarion is... could that be a problem at all?
>
> - -chris
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>
>   


-- 
Regards

Gabe Wong
Private JVM JAVA Hosting Automation
http://www.ngasi.com


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