[Building Sakai] JAVA_OPTS issue

[Steve Swinsburg]

Hi,

We have an install that only has about that amount of memory and users, but not many concurrent users. Also, some tools are heavier on the session state than others. So the answer is it depends on your situation. To be on the safe side you would aim for 2Gb, IMO, so if you can get a 64bit JVM, then you can increase the memory available to it if you need.

cheers,
Steve



On 24/01/2011, at 5:31 PM, Shoaib Chaudhary wrote:

> Hello Steve, 
> 
> Thanks for replying. 
> 
> I just wanted to know for Sakai is it good to use this much memory -- 1175 MB -- that is allocated. Total number of users are 4000 in our case. If it is not enough what is the solution. should I make more VMs or use 64 bit JVM. 
> 
> many thanks again. 
> 
> Regards 
> MUHAMMAD SHOAIB | Software Engineer  
> National University of Computer and Emerging Sciences
> A. K. Brohi Road (Near Police Line) H11/4 Islamabad 
> Tel +92-(51)-111-128-128 Ext 344  Cell +92-(334)-5577712
> muhammad.shoaib at nu.edu.pk 
> 
> 
> On Mon, Jan 24, 2011 at 11:26, Steve Swinsburg <steve.swinsburg at gmail.com> wrote:
> Hi,
> 
> This is most likely to do with a 32 bit JVM.
> 
> Why can't I get a larger heap with the 32-bit JVM?
> 
> The maximum theoretical heap limit for the 32-bit JVM is 4G. Due to various additional constraints such as available swap, kernel address space usage, memory fragmentation, and VM overhead, in practice the limit can be much lower. On most modern 32-bit Windows systems the maximum heap size will range from 1.4G to 1.6G. On 32-bit Solaris kernels the address space is limited to 2G. On 64-bit operating systems running the 32-bit VM, the max heap size can be higher, approaching 4G on many Solaris systems.
> 
> As of Java SE 6, the Windows /3GB boot.ini feature is not supported.
> 
> If your application requires a very large heap you should use a 64-bit VM on a version of the operating system that supports 64-bit applications. See Java SE Supported System Configurations for details.
> 
> 
> ref: http://www.oracle.com/technetwork/java/hotspotfaq-138619.html#gc_oom
> 
> cheers,
> Steve
> 
> 
> On 24/01/2011, at 5:16 PM, Shoaib Chaudhary wrote:
> 
>> Dear All, 
>> 
>> I am using Tomcat 5.5.31 from JVM 6 on Windows server 2003 Enterprise Edition. I have made Virtual machine with 2.5 GB RAM. Original System RAM is 4 GB. but when I set JAVA_OPTS XMX value more then 1175 tomcat doesn't run. Can any one help me out in this regards. I want to utilize whole 4 GB memory of my machine for deploying Sakai 2.7.1. What are the maximum value for Java_opts parameters.  
>> 
>> Regards 
>> MUHAMMAD SHOAIB | Software Engineer  
>> National University of Computer and Emerging Sciences
>> A. K. Brohi Road (Near Police Line) H11/4 Islamabad 
>> Tel +92-(51)-111-128-128 Ext 344  Cell +92-(334)-5577712
>> muhammad.shoaib at nu.edu.pk 
>> 
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