Bug 682612

Summary:	Rhel6 cannot support 32GB memory
Product:	[Fedora] Fedora	Reporter:	lvxueguan <satbfydwno>
Component:	kernel	Assignee:	Kernel Maintainer List <kernel-maint>
Status:	CLOSED NOTABUG	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	14	CC:	gansalmon, itamar, jonathan, kernel-maint, madhu.chinakonda
Target Milestone:	---
Target Release:	---
Hardware:	i686
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-03-08 07:10:36 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description lvxueguan 2011-03-07 03:02:47 UTC

Description of problem:
My computer has a memory of 32GB,I know rhel6 has a PAE enabled kernel by default.
but the command "free -m" only shows total memory of 16GB ,why?

Comment 1 lvxueguan 2011-03-08 01:02:06 UTC

On fc12(kernel:2.6.32),there is a rpm package called kernel-PAE ,when the system has no PAE ,the recognized total memory is 4GB,after install kernel-PAE the recognized total memory is 32GB.
Compile kernel on rhel6(kernel:2.6.32) cannot produce package kernel-PAE,but rhel6 has a PAE enabled kernel by default,and now the recognized total memory is 16GB,why,(I know the PAE is integrated in kernel ,or the recognized total memory will be 4GB), why it is not 32GB.

Comment 2 Chuck Ebbert 2011-03-08 07:10:36 UTC

Maximum supported memory for Red Hat Enterprise Linux 6 with the 32-bit PAE kernel is 16GB:
http://www.redhat.com/rhel/compare/

The hugemem kernel that supported more than that is no longer provided in version 5 and 6, I assume because x86_64 can support large amounts of memory much better.