[rhn-users] Unable to boot with more than 4GB of RAM

[Doerbeck, Christoph]

PAE is a hardware/software trick that allows a 32bit system to address
36-bits of memory (If I recall correctly).  In any case, it technically
allows up to 64 Gigs of ram. However, it's not linear and is broken into
3.2 (ish) gigabyte pages of memory that can be addressed by a PAE
enabled kernel.  Your hardware also has to support PAE (which I would
think your box does? What is your hardware?)
 
The ELsmp kernel in RHEL3 is PAE enabled, but I think it only supports
up to 16 GB of ram (maybe it's 32).
You'll need to install the ELhugemem kernel to go higher.
 
Are you sure you are running ELsmp?  What does 'cat /proc/meminfo' show?

	-----Original Message-----
	From: Mei.Zhang at alltel.com [mailto:Mei.Zhang at alltel.com] 
	Sent: Thursday, July 21, 2005 3:06 PM
	To: rhn-users at redhat.com
	Subject: RE: [rhn-users] Unable to boot with more than 4GB of
RAM
	
	
	You may need 64bit rhel

	what is PAE enabled kernel?        

		-----Original Message-----
		From: rhn-users-bounces at redhat.com
[mailto:rhn-users-bounces at redhat.com]On Behalf Of Serge Bianda
		Sent: Thursday, July 21, 2005 3:01 PM
		To: rhn-users at redhat.com
		Subject: [rhn-users] Unable to boot with more than 4GB
of RAM
		
		

		Hello,

		 

		I had three machines that we migrated from SuSE 9 to
RHEL 3 ES, and Under SuSE the amount of memory was showing correctly as
6GB, but under RHEL when I do a dmesg I get the following report:

		 Warning only 4GB will be used.

		Use a PAE enabled kernel.

		 

		Any Ideay on how to resolve that and have RHEL ustilize
the maximum memory? I have the following kernel loaded: 2.4.21-27.ELsmp

		 

		Thanks

		 

		Serge

		 

	
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