LinuxQuestions.org - Red Hat AS 4 update 6 16GB mem not stable

- Linux - Enterprise (https://www.linuxquestions.org/questions/linux-enterprise-47/)

- - Red Hat AS 4 update 6 16GB mem not stable (https://www.linuxquestions.org/questions/linux-enterprise-47/red-hat-as-4-update-6-16gb-mem-not-stable-599872/)

Red Hat AS 4 update 6 16GB mem not stable

Hey folks, I have a Red Hat AS 4 update 6 box with more than 16 gb of Ram that keeps rebooting at random times. I see this in the messages file:

3, Param2=5
Nov 14 20:21:18 bl-backup-01a SQLAnywhere(nb_bl-backup-01a): Starting checkpoint of "BMRDB" (BMRDB.db)
at Wed Nov 14 2007 20:21
Nov 14 20:21:18 bl-backup-01a SQLAnywhere(nb_bl-backup-01a): Finished checkpoint of "BMRDB" (BMRDB.db)
at Wed Nov 14 2007 20:21
Nov 14 20:33:47 bl-backup-01a syslogd 1.4.1: restart.
Nov 14 20:33:47 bl-backup-01a syslog: syslogd startup succeeded
Nov 14 20:33:47 bl-backup-01a kernel: klogd 1.4.1, log source = /proc/kmsg started.
Nov 14 20:33:47 bl-backup-01a kernel: Linux version 2.6.9-55.0.12.ELsmp (brewbuilder@hs20-bc1-6.build.r
edhat.com) (gcc version 3.4.6 20060404 (Red Hat 3.4.6-8)) #1 SMP Wed Oct 17 08:19:30 EDT 2007
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-provided physical RAM map:
Nov 14 20:33:47 bl-backup-01a kernel: ********************************************************
Nov 14 20:33:47 bl-backup-01a kernel: * This system has more than 16 Gigabyte of memory. *
Nov 14 20:33:47 bl-backup-01a kernel: * It is recommended that you read the release notes *
Nov 14 20:33:47 bl-backup-01a kernel: * that accompany your copy of Red Hat Enterprise Linux *
Nov 14 20:33:47 bl-backup-01a kernel: * about the recommended kernel for such configurations *
Nov 14 20:33:47 bl-backup-01a kernel: ********************************************************
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 0000000000000000 - 000000000009f400 (usable)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 000000000009f400 - 00000000000a0000 (reserved)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 0000000000100000 - 00000000cfed70c0 (usable)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 00000000cfed70c0 - 00000000cfee7cd4 (ACPI data)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 00000000cfee7cd4 - 00000000d0000000 (reserved)
Nov 14 20:33:47 bl-backup-01a syslog: klogd startup succeeded
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 00000000fee00000 - 00000000fee10000 (reserved)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 00000000ffc00000 - 0000000100000000 (reserved)
Nov 14 20:33:47 bl-backup-01a kernel: BIOS-e820: 0000000100000000 - 000000042ffff000 (usable)
Nov 14 20:33:47 bl-backup-01a kernel: 16255MB HIGHMEM available.
Nov 14 20:33:47 bl-backup-01a kernel: 896MB LOWMEM available.

Is this a memory addressing problem by the installed kernel? How do I fix it? Is there something else I should be looking at as the culprit for the reboots?

Any help appreciated, thanks in advance.

Huff

Hmmm..........
Nov 14 20:33:47 bl-backup-01a kernel: Linux version 2.6.9-55.0.12.ELsmp

I think that there is a kernel update (kernel-2.6.9-67) that came out around November 8, 2007 that fixed some memory issues.

Could it be that the server wants the HUGEMEM kernel ?

from the RHEL 4 Release notes..

Quote:

kernel

This section contains notes relating to the Red Hat Enterprise Linux 4 kernel.

* 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.)

something to look into at least..