On this page we gather usefull tips on how to make User-mode-linux run as
optimized as possible. Most of these tips are mentioned on other howtos
around. The newest tricks are usually discussed on the uml mailing lists, so
pay attention there if you want the latest news.
Patching the host
kernel with this patch gives a signifficant boost
in both security and performance. Please correct me if i am wrong. You can
find out more on this on blaisorblades homepage: http://www.user-mode-linux.org/~blaisorblade
It is my impression that most people who use uml for something also have
SuSe 9.2 ship their default kernel with this patch applied. If you know of
other distributions which do that, please let me know.
TMPDIR using tempfs
User-mode-linux creeates files on /tmp for their memory. Making sure they
are placed in a ram-based filesystem will increase the speed. This is easily
done (as root):
mount -t tmpfs -o size=2048m,mode=1777 none /tmp/mln
echo "setenv TMPDIR /tmp/mln" >> /etc/screenrc
This little snippet assigns 2GB of virtual filesystem. Some say you should
assign as much as all your UMLs have booked but not more than RAM + SWAP on
your host system. Please adjust it to your own needs. We also assume that
the projects use screen and not xterm. The last line will make sure the
environment variable is exported to the screen process (since it sets up its
own). If you want it to count for xterm too, make sure it is a environment
variable for the shell which runs the mln command.