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25 Apr 2012 Change how the swap memory behave in Ubuntu

This post is just a cut and paste job from the Ubuntu SwapFaq for my future reference Ubuntu installation.

The swappiness parameter controls the tendency of the kernel to move processes out of physical memory and onto the swap disk. Because disks are much slower than RAM, this can lead to slower response times for system and applications if processes are too aggressively moved out of memory.

  • swappiness can have a value of between 0 and 100
  • swappiness=0 tells the kernel to avoid swapping processes out of physical memory for as long as possible
  • swappiness=100 tells the kernel to aggressively swap processes out of physical memory and move them to swap cache

The default setting in Ubuntu is swappiness=60. Reducing the default value of swappiness will probably improve overall performance for a typical Ubuntu desktop installation. A value of swappiness=10 is recommended, but feel free to experiment. Note: Ubuntu server installations have different performance requirements to desktop systems, and the default value of 60 is likely more suitable.

To check the swappiness value

# cat /proc/sys/vm/swappiness

To change the swappiness value A temporary change (lost on reboot) with a swappiness value of 10 can be made with

# sudo sysctl vm.swappiness=10

To make a change permanent, edit the configuration file with your favorite editor:

# gksudo gedit /etc/sysctl.conf

Search for vm.swappiness and change its value as desired. If vm.swappiness does not exist, add it to the end of the file like so:

vm.swappiness=10

Save the file and reboot.

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09 Dec 2011 Disable IPv6 on Ubuntu 11.10

This is a short HOWTO on disabling IP version 6 support on your ethernet devices like eth0 on Ubuntu 11.10.
I guess you can do this on earlier version of Ubuntu as well.

  • Add the following line to the end of the file /etc/sysctl.conf (as root or use sudo)

  • net.ipv6.conf.all.disable_ipv6 = 1
  • Run the following command to make this change effective immediately

    # sudo sysctl -p

    A result from this command could be like this

    net.ipv6.conf.all.disable_ipv6 = 1

    To check that IPv6 has been disabled or not, run the following command from your console window

    # ip a | grep inet

    IPv6 has been disabled if this command does not return any IPv6 addresses.

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    19 Sep 2011 Fix low volume issue in Ubuntu 11.04

    This post is a short howto to fix/workaround the problem with low volume in some Ubuntu 11.04 installations.
    The fix for me was to open a console window (as the user I’m logged in with) and start the alsamixer

    # alsamixer

    You will then see the alsamixer window. Use the left/right arrow keys and choose the device you would like to configure. In my case it was the headphone.

    Choose which sound card you would like to configure on the headphone by pressing the F6-key. Make your choice and press the Enter-key.

    Use your up/down arrow keys to choose the right volume for your configuration. You should have some audio playing while you configure to determine the right value.

    Press the Esc key to exit alsamixer when you have found the right volume. Your settings are persistent and will survive a reboot.

    You are now done with configuring your sound card.

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    17 Apr 2011 Choosing Gnome as default Desktop in Ubuntu 11.04

    This post describes how you can change from the Unity Desktop environment that is the default desktop environment to the Gnome Desktop in Ubuntu 11.04 (Natty Narwhal) Beta.
    The desktop environment I like to use is the desktop named Ubuntu Classic and you can change to this desktop by going to (or searching for) System Settings -> System-> Admin -> Login.

    Here you can choose between

    • Ubuntu Classic (No effects)
    • Ubuntu (Safe Mode)
    • Ubuntu
    • XBMC
    • Ubuntu Classic
    • Recovery Console

    Log out of the Unity desktop after choosing Ubuntu Classic and pressing the Close button.

    You can now choose your desired desktop environment from the bottom of the screen. If you would like to use the Gnome Desktop environment like the one we are used to in Ubuntu 10.10 and earlier, just choose Ubuntu Classic and login again.

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    12 Apr 2011 Change console language i Ubuntu

    A short description on how to change the console language in Ubuntu 10.04 LTS Server but it should work on other Debian flavours as well.

    # dpkg-reconfigure console-data

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