Number of processors and number of JVM on Jas Servers

antoine_mpo

Reputable Poster
Hi list,

We're gonna change our jas configuration.
We planned to install 3 JVM per server (on 2 Windows 2000 jas servers, with 2 processors and 4 Go of RAM, using Websphere 4), using 768 Mo of memory each.
But the consultant that help us to set this up was wondering if it would be better to install 2 JVM of 1 Go of memory instead of 3 of 768 Mo. He thinks that may be windows would better manage the CPU with 2 JVM for 2 processors, but he's not really sure, and it's not really easy to test.

Do you have some feedback or opinion on that matter ?

Thanks for your help.

Cheers,
 
Antoine, generally each VM in Websphere operates optimally on 1 processor. Therefore, if you have a 2 processor board, you'd want to have 2 VMs on that machine. Each VM does well to have between 1GB - 1.5GB of memory. The OS itself does well with 1GB of memory. So, if you're running 2 processors, you'd have from 2-3GB of memory for the VMs plus 1GB of memory for the OS. That means that 4GB total would be just fine for 2 VMs running on that one machine. That's been my experience. Good luck!
 
Hi wayne,

Thanks for your answer.
Did you experienced to have more JVM than processors, having poor performance, and then changed it to have 1 jvm per processor and noticed better performance ?
 
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