RHEL 5.2 not recognizing memory beyond 4GB

[arkie]

Hi,

A rx2660 has 8GB of Physical memory installed, but RHEL 5.2 is showing only 4GB.

Can anyone pls help?

Thanks in advance

[Goran Koruga]

Does the kernel you're using have CONFIG_HIGHMEM64G enabled?

Goran

[arkie]

Hi Goran,

Pls guide me on how to check this & confirm

[Goran Koruga]

Hello.

Well I suppose you're using the kernel from RH so grep for it in its config file in /boot.

Perhaps you just need proper kernel package installed, i.e. something similar to "bigmem" kernels in Debian.

Regards,
Goran

[Steven E. Protter · Accepted solution]

Shalom,

The only version of Red Hat that works on an Itanium Server is RHEL for IA-64.

It should without any modification, being pure 64 bit, memory beyond 4 GB.

There is no hugemem or special kernel settings for IA-64 Red Hat.

Please post the following output for further diagnosis:

free

vmstat

Please confirm on the hardware side that all 8 GB of ram are working.

SEP

[Goran Koruga]

Doh, so much for knowing what rx2660 is ;)

[arkie]

The issue is resolved. We were using the xen kernel. Actually, during the installation, we did not deselect "Virtualization" and that had left our the ia64 kernel.

The ia64 kernel is showing 8GB memory now.

One more unique thing was observed - the xen kernel does not show the service startups during booting, and, we couldn't get into the Single-user mode with the xen kernel.

Thanks all.

[arkie]

Can anyone lend me the procedure to enable CONFIG_HIGHMEM64G in a kernel (where it is not enabled)?

Thanks again!

[Goran Koruga]

Hi.

I have mislead you with CONFIG_HIGHMEM64G option because I had no idea this is an Itanium machine. Sorry about that.

This option is only relevant for 32bit kernels running on x86.

Regards,
Goran

[arkie]

Hi Goran,

It was not clear on my part about the architecture.

But, it very important to know how to configure the CONFIG_HIGHMEM64G option even in case of 32bit kernels running on x86. Can you provide me some leads with that.

Thanks!