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List:       redhat-list
Subject:    attempting to change SHMMAX
From:       Adam Sleight adams () linearcorp ! com
Date:       2000-05-31 18:45:04
[Download RAW message or body]

don't need to recompile the kernel to increase your SHMMAX
just add the following to the end of /etc/rc.d/rc.local file

if [ -f /proc/sys/kernel/shmmax ]; then
    expr 128 \* 1024 \* 1024 > /proc/sys/kernel/shmmax
    fi

no need to reboot either  just execute rc.local
/etc/rc.d./rc.local
then
cat /proc/sys/kernel/shmmax 
or ipcs -lm like you said

btw I learned this from the documentation from Time Navigator (backup software)

On Tue, 30 May 2000 20:00:07 -0400
 Christina Clark <ckclark@us.oracle.com> wrote:
#Greetings,
#
#I am setting up an Oracle 8i Server on Intel RedHat 6.2 (kernel
#2.2.14-5.0).
#
#I am very happy with the way the kernel is behaving and only want to
#increase SHMMAX from 32 megs to 128 megs (half my physical memory).
#
#The detailed steps I took to change and recompile the kernel follow
#below and the process went fine, but when I do an
#ipcs -lm
#after booting on the new kernel, I still see max seg size (kbytes) =
#32768
#
#Can anyone explain why I am not seeing any change?
#
#Thanks,
#ckclark
#
#
#Here is what I did.
#[root@ckclark-pc src]# cd /usr/src
#(copied to a working directory with o suffix for oracle  --paranoia)
#[root@ckclark-pc src]# cp -r linux-2.2.14-5.0 linux-2.2.14-5.0o
#Made following change to Makefile:
#EXTRAVERSION = -5.0o
#
#Made some links:
#[root@ckclark-pc src]# ln -s linux-2.2.14-5.0o linux
#[root@ckclark-pc src]# cd linux/include
#[root@ckclark-pc include]# ln -s asm-i386 asm
#[root@ckclark-pc asm]#
#Edited /usr/src/linux-2.2.14-5.0o/include/asm/shmparam.h to have:
#
##define SHMMAX 0x8000000                /* max shared seg size (bytes)
#*/
#
#[root@ckclark-pc asm]# cd ../../
#Created my .config file to be like the one I'm already using:
#[root@ckclark-pc linux]# make oldconfig
#Make .depend, .hdepend, recompile
#[root@ckclark-pc linux]# make dep; make clean; make bzImage; make
#modules; make modules_install
#
#Copied bzImage and System.map to /boot as vmlinuz-2.2.14-5.0o and
#System.map-2.2.14-5.0o.
#Created links from /boot/vmlinuz and /boot/System.map to these files.
#Setup lilo.conf:
#boot=/dev/hda
#map=/boot/map
#install=/boot/boot.b
#prompt
#timeout=50
#linear
#default=linuxo
#
#image=/boot/vmlinuz-2.2.14-5.0
#        label=linux
#        read-only
#        root=/dev/hda10
#
#image=/boot/vmlinuz-2.2.14-5.0o
#        label=linuxo
#        read-only
#        root=/dev/hda10
#
#Ran lilo and rebooted with the new kernel.

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