We recently had a drive failure on our development server and while going through the steps of re-installing CentOS, I came across an odd problem.

The server in question has 3 drives:

• Drive has the OS on it
• Drive 2 and 3 is a software RAID1 with Device Mapper (DM)

The problem: CentOS installer would get to a certain point after selecting Language and keyboard option, then hang. By switching to a virtual console to see the debug messages, the installer was stuck on:

CentOS install hangs with moving (1) to step findrootparts

I tried CentOS 4.4, CentOS 5.4 net install and CentOS 5.0. Every single one had the same problem!

Come to find out, there is a bug with RedHat , which also effects CentOS, that causes the installation to mess up when attempting to detect/enable/whatever the software raid array. Here is a description of bug 517556

The solution is to boot the install with the "nodmraid" option, like so:

At the boot prompt, type:

linux nodmraid

Or if you use text install like me type: 

linux nodmraid text

And that worked! Hope this helps someone