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how to utilize more than 3 GB RAM in RHEL5

 
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Occasional Contributor

how to utilize more than 3 GB RAM in RHEL5

my RHEL5 system cannot see memory more then 3.5 GB. I have 8 GB Memeory in my system. can you please suggest


Regards,
Adeel
3 REPLIES 3
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Honored Contributor

Re: how to utilize more than 3 GB RAM in RHEL5

You are probably running a 32-bit version of the RHEL5 operating system. To check, use the command "uname -m". If it reports "i686", you are running a 32-bit version. A 64-bit version would report e.g. "x86_64" (or "IA64" if you have an Itanium CPU).

In a 32-bit Linux system, no process can see more than a total of 4 GB of address space. Some of this address space may be claimed by kernel and inter-process shared memory. If your hardware (CPU & system board) supports Physical Address Extension (PAE), you can use more than 4 GB of memory... but your process size is still limited to 4 GB or less.

If you have 8 GB of memory in your system and it supports PAE, you can easily run 3 processes requiring 2 GB of memory each... but you cannot run even a single process that would require 4.1 GB.

With a 64-bit version of the OS, this restriction does not exist: with 8 GB of memory, you can run a process that requires e.g. 7.9 GB of memory.

MK
MK
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Exalted Contributor

Re: how to utilize more than 3 GB RAM in RHEL5

Shalom,

The 32 bit OS limit is 16 GB.

So its not an OS issue. Could be you are running it on hardware that does not recognize more them certain amount of memory.

Please provide hardware details and free output.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
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Honored Contributor

Re: how to utilize more than 3 GB RAM in RHEL5

Hi Adeel,

Take a look through this advisory:

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c00883105〈=en&cc=us&taskId=101&prodSeriesId=3239482&prodTypeId=12169

Cheers,

Rob