RH4AS large memory kernel config instructions

underonesun · 08-13-2007, 02:38 PM

Seeing this on a new box:

********************************************************
* This system has more than 16 Gigabyte of memory. *
* It is recommended that you read the release notes *
* that accompany your copy of Red Hat Enterprise Linux *
* about the recommended kernel for such configurations *
********************************************************

Haven't done redhat stuff for a while and can't find the release notes. Looked on redhat.com, etc. All their links to release notes were broken*.

Maybe someone can point me to release notes or instructions for building a large memory kernel for redhat. Or do I just up date to some redhat kernel?

*Error from redhat's broken links:

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Lenard · 08-13-2007, 03:05 PM

From: http://www.redhat.com/docs/manuals/e...-notes/as-x86/

Quote:

Red Hat Enterprise Linux 4 includes a kernel known as the hugemem kernel. This kernel supports a 4GB per-process user space (versus 3GB for the other kernels), and a 4GB direct kernel space. Using this kernel allows Red Hat Enterprise Linux to run on systems with up to 64GB of main memory. The hugemem kernel is required in order to use all the memory in system configurations containing more than 16GB of memory. The hugemem kernel can also benefit configurations running with less memory (if running an application that could benefit from the larger per-process user space, for example.)
Note

To provide a 4GB address space for both kernel and user space, the kernel must maintain two separate virtual memory address mappings. This introduces overhead when transferring from user to kernel space; for example, in the case of system calls and interrupts. The impact of this overhead on overall performance is highly application dependent.

To install the hugemem kernel, enter the following command while logged in as root:

rpm -ivh <kernel-rpm>

(Where <kernel-rpm> is the name of the hugemem kernel RPM file — kernel-hugemem-2.6.9-1.648_EL.i686.rpm, for example.)

underonesun · 08-13-2007, 04:10 PM

Quote:

Originally Posted by Lenard

From: http://www.redhat.com/docs/manuals/e...-notes/as-x86/

Thanks. Is it a cop out that they don't tell me how to determine the rpm package name that I need? Or should I know that somehow?

How is one supposed to know that?

syg00 · 08-13-2007, 05:02 PM

I don't do RH, but something like

Code:

kernel-hugemem-`uname -r`

might be a start.
Note thems is backticks, not single quotes.