[CentOS] What is the best strategy for updating CentOS from 4 to 5?

[John R Pierce]

  On 07/30/10 10:26 PM, Todd Cary wrote:
> No doubt I have waited just a little too long, but I think it is time to
> upgrade before it is not supported.  My server is not heavily used
> (mostly for viewing images) and my Admin skills are better than beginner
> but NOT guru.

backup your files, configurations, etc, wipe the system, clean install 
centos 5, restore your configurations and files.

if all your user and server files are on seperate file systems from /, 
/var, /usr, then you may be able to leave them inplace as long as you're 
careful with the installer not to touch your data filesystems.