HOWTO: Enable prelink

**jdong** · October 24th, 2004

Prelink is in universe. I use it on my Ubuntu system without issues, but do google about Prelink and do your research before trying it out.

How to enable prelink:

1. Activate Ubuntu universe sources. The procedure is well-documented by Ubuntu.
2. use apt-get or synaptic to install prelink.
3. Open /etc/default/prelink with your favorite editor, as sudo/root.
4. Change PRELINKING=unknown from unknown to yes.
5. Adjust the other options if you know what the heck you're doing. Defaults work well.
6. To start the first prelink (the longest one!), run sudo /etc/cron.daily/prelink

In the future, prelink performs a quick prelink (a less-than-1-minute procedure on most systems) daily, usually at midnight. Every 14 days, or whatever you changed it to be, a full prelink will run.

If you just did a major apt-get upgrade that changed systemwide libraries (i.e. libc6, glibc, major gnome/X libs, etc etc etc) and experience cryptic errors about libs, rerun step 6.

To undo prelink, change step 4 from yes to no, then rerun step 6.

WARNING:
An amd64 users in another thread (http://ubuntuforums.org/showpost.php...3&postcount=16) reports having experienced trouble with AMD64 prelinking. I have NOT tried prelinking on anything other than an i386!

**wallijonn** · January 16th, 2005

Man, I was looking for this link the longest. Good stuff.

**Tichondrius** · January 18th, 2005

Cool, that seems to work, a few executables and libraries seem to have been updated. But how much of a performance boost is this, and how can it be measured ?

**Technoviking** · January 18th, 2005

Great how-to.
Thanks

**Rene_S** · March 11th, 2005

Cool, I learn something new everyday. Thanks for the Howto.

**bored2k** · March 11th, 2005

Originally Posted by Rene_S

Cool, I learn something new everyday. Thanks for the Howto.

How many hours would prelinking last on a 15gb drive?40gb?
Can I use my PC on this period?

**Xian** · March 11th, 2005

Originally Posted by bored2k

How many hours would prelinking last on a 15gb drive?40gb?
Can I use my PC on this period?

- It took me under 5 min on a 15GB partition with my AthonXP 3200.
- You can easily still use your computer.

**bored2k** · March 11th, 2005

Originally Posted by Xian

- It took me under 5 min on a 15GB partition with my AthonXP 3200.
- You can easily still use your computer.

thanks, I was a little scared as I basically eat off it and my communication with the world outside my parking lot lies on Noir -thats her name...pretty sexy.

**Xian** · March 14th, 2005

Originally Posted by jdong

To start the first prelink (the longest one!), run sudo /etc/cron.daily/prelink

What it the difference between running this and issuing the command?:

# sudo nice -15 prelink -Rmvaf

**jdong** · March 15th, 2005

the cron scripted prelink is more Debian oriented. At heart, it certainly calls the command you mentioned. However, it redirects output to a logfile in /var/log, allows incremental prelinking, and performs more "civilized" goodies.