Comments on: Performance tuning with System Control (sysctl) in Ubuntu

By: vancouverite

vancouverite — Thu, 05 May 2011 00:24:09 +0000

This comes up with Avast antivirus in Ubuntu. If you get an error when trying to start Avast! it is likely because the kernel.shmmax variable (shared memory max) is too small and needs to be increased:

$ sudo gedit /etc/sysctl.d/60-user.conf

In this file put:
# this is to make avast work
kernel.shmmax = 128000000

This will become active after reboot, but if you want to get it working before your next reboot:

$ sudo sysctl -p /etc/sysctl.d/60-user.conf

By: Klaver

Klaver — Wed, 30 Jun 2010 10:05:12 +0000

A complete sysctl.conf with kernel tuning and network security hardening optimizations for dedicated server systems at high-speed networks with loads of RAM and bandwidth available.
Optimised and tuned for high-performance web/ftp/mail/dns servers with high connection-rates.

Available here: https://klaver.it/linux/sysctl.conf

By: Anonymous

Anonymous — Thu, 20 May 2010 16:47:24 +0000

It can actually be made easier and without touching the original sysctl.conf. Just make file named something like 60-user.conf in the /etc/sysctl.d/ and put this stuff into it.

By: Mike Bee

Mike Bee — Tue, 24 Mar 2009 21:14:02 +0000

??? If one messes up, is there a way to boot from cd, mount the hard drive, then cp /etc/sysctl.conf.back /etc/sysctl.conf

By: Linux Blade Guy

Linux Blade Guy — Thu, 30 Oct 2008 21:37:01 +0000

Maybe it’s just me, but I never ever recommend randomly changing tuning settings without knowing WHY you are changing them or what they’re supposed to improve. After you go and mess with all of this, what are the tests you can do to see the improvements? Would you open the hood of your car and randomly turn adjusting screws without knowing what you were doing?

By: SmurfTheWeb

SmurfTheWeb — Thu, 30 Oct 2008 08:36:15 +0000

The best idea is to perform the all important first step - backup the file!
sudo cp /etc/sysctl.conf /etc/sysctl.conf.old

By: Giker_MIKE

Giker_MIKE — Sun, 26 Oct 2008 08:17:21 +0000

i was found on other ubu tweak guide to set “vm.swappiness” to 0, not like in this solution to 1. So can someone tell me who have a better idea? Coz im confiused now :s

By: malaeum

malaeum — Fri, 24 Oct 2008 15:23:16 +0000

trolling the right way seems to be an oxymoron

By: LiveWire

LiveWire — Fri, 24 Oct 2008 02:50:28 +0000

No, it’s http://www.google.com/linux .

If you want to troll, do it the right way.

By: Brett

Brett — Thu, 23 Oct 2008 17:13:35 +0000

You can find both a brief and a verbose explanation by using this really cool new site. Its really helpful for learning new things! http://www.google.com

By: admin

admin — Thu, 23 Oct 2008 06:02:56 +0000

@joseph

When you edit sysctl.conf file and add those values and run sysctl -p this should be persist after reboot

By: Joseph

Joseph — Thu, 23 Oct 2008 02:26:16 +0000

So how do you make these setting persist after reboot? Thanks for the article.

By: Erik

Erik — Thu, 23 Oct 2008 00:51:53 +0000

Where can I find a brief explanation of what each of these settings does?

By: Vadi

Vadi — Thu, 23 Oct 2008 00:14:37 +0000

pro-tip: don’t do this unless you know what you’re doing.

(or don’t complain when you have to reinstall)