Sunday, May 19, 11:36 am

SHMMAX share Linux memory

Written by Mel Kham on February 20, 2010. Posted in Linux tutorials

The Linux kernel has many parameters that may be tuned, and are not well documented. Shared memory has been a big issue with big application like Oracle, Tibco, Webmethods on linux, This is the way to show you how to set limit of your used memory .

To determine the maximum size of a shared memory segment, run:

# cat /proc/sys/kernel/shmmax

2147483648

The default shared memory limit for SHMMAX can be changed in the proc file system without reboot:

# echo 2147483648 > /proc/sys/kernel/shmmax

Alternatively, you can use sysctl(8) to change it:

# sysctl -w kernel.shmmax=2147483648

To make a change permanent, add the following line to the file /etc/sysctl.conf (your setting may vary). This file is used during the boot process.

# echo "kernel.shmmax=2147483648" >> /etc/sysctl.conf

{loadposition user9}

Related Articles By Tags:

{loadposition user1}

For questions please refer to our Q/A forum at : http://ask.unixmen.com

kernel

Linux

memory

shmmax

1 Comment(s)

Mel Kham

Founder of Unixmen, Living in Amsterdam. Am working in my free time to help people to understand the Opensource and to explain them in easy way how to make the fist steps to the the light. Working day and night with my Co-founder Zinovsky to keep this website live even with less resources.

haider abbas

I add
kernel.shmall = 4294967296
kernel.shmmax = 4294967296
in /etc/sysctl.conf

to increase shared memory
but when I run the command sysctl -a|grep shmmax it shows
root@haider-desktop:~# sysctl -a|grep shmmax
kernel.shmmax = 0
error: "Invalid argument" reading key "fs.binfmt_misc.register"
error: permission denied on key ‘net.ipv4.route.flush’
error: permission denied on key ‘net.ipv6.route.flush’
root@haider-desktop:~#

I again run the command /etc/sysctl.conf -w
then it shows
root@haider-desktop:~# /etc/sysctl.conf -w
bash: /etc/sysctl.conf: Permission denied
root@haider-desktop:~#

however I am the running these command by root
I dont understand what is going on what is the actual problem
again by
ipcs -l it get

—— Shared Memory Limits ——–
max number of segments = 4096
max seg size (kbytes) = 0
max total shared memory (kbytes) = 0
min seg size (bytes) = 1

—— Semaphore Limits ——–
max number of arrays = 128
max semaphores per array = 250
max semaphores system wide = 32000
max ops per semop call = 32
semaphore max value = 32767

—— Messages: Limits ——–
max queues system wide = 1668
max size of message (bytes) = 8192
default max size of queue (bytes) = 16384

root@haider-desktop:~#

with regards
Dr. Haider Abbas

Like us on Facebook

This week Top Posts

Top Things to do After Installing Ubuntu 13.04 ‘Raring Ringtail’ : Ubuntu 13.04 Raring Ringtail final is almost out. The final release it scheduled for release on Apri...0 comment(s) | by M. Zinoune
Howto: Upgrade to Ubuntu 13.04 Raring Ringtail from 12.04, 12,10 | Desktop & Server : Updated 05-04-2013: Ubuntu 13.04 Raring Ringtail will be released Soon, If you have ubuntu 12,10, 12...0 comment(s) | by M. Zinoune
Unix/Linux File Recognition. Did You Know? : Did you know that Unix and Linux has no concept of a file extension? What is a file name extension? ...0 comment(s) | by Ambition
Install lamp with 1 command in Ubuntu 12.10, 13.04 Raring Ringtail & LinuxMint13 : Updated: 10/09/2012 :LAMP (Linux, Apache, MySQL and PHP) is an open source Web development platform ...0 comment(s) | by Mel Kham
Howto- Resolve nosound problem on Ubuntu 13.04 Raring Ringtail,12.10 and Older : Updated 05/04/2013 : One of the common issues facing Ubuntu users after installing or upgrading Ubun...0 comment(s) | by M. Zinoune
Configure conky-Lua in Ubuntu (12.10 & 13.04 Raring Ringtail), Fedora, debian and LinuxMint | Howto Conky : Updated 05-04-2013: Conky is a free, light-weight system monitor for X, that displays any informatio...0 comment(s) | by M. Zinoune