[CentOS] Not seeing all memory in CentOS 5.1 x86_64

[Akemi Yagi]

On Tue, Jun 10, 2008 at 5:43 PM, Ruslan Sivak <russ at vshift.com> wrote:
> I'm running CentOS 5.1 with all updates, and the xen kernel.  For some
> reason the OS is not seeing the full amount of ram.
> #uname -a
> Linux CentOS-VM-A 2.6.18-53.1.21.el5xen #1 SMP Tue May 20 10:03:27 EDT 2008
> x86_64 x86_64 x86_64 GNU/Linux
>
> # free
>            total       used       free     shared    buffers     cached
> Mem:       6104064    3445136    2658928          0    1412236    1515032
> -/+ buffers/cache:     517868    5586196
> Swap:      2031608          0    2031608
>
>
> On another box with identical hardware, I see
> # free
>            total       used       free     shared    buffers     cached
> Mem:       5038080    1818980    3219100          0     145208    1148608
> -/+ buffers/cache:     525164    4512916
> Swap:      2031608        152    2031456
>
>
> Both of these boxes have 8GB of ram.  Is there a reason I'm not seeing all
> of it?
> Russ

Wonder if this is related to a known issue with the xen kernel.

http://www.centos.org/modules/newbb/viewtopic.php?topic_id=12491&forum=38

Or

http://bugs.centos.org/view.php?id=1905

You might want to try the grub with a patch offered in there.

Akemi