What is the best practices recommended way to reboot a OES SP2 - Linux
server that may or may not be part of a cluster? SLES9, SLES10?? Does
Linux version or distro matter on the reboot procedure? Thanks for any
answers in advance.

Basic question, yes. But, when I googled for the answer I was surprised
about all the contradicting information.

Here is list of (many ways) what I have found to restart/reboot a linux
1. init 0 - "files synchronized, system left in state where it is safe
to turn off." Source: CLP study guide E Dulaney

2. init 6 - "same result as runlevel 0, except restarts.
Source: CLP study guide by Dulaney

(I'm assuming that init 6 is safe way to restart since it
does same as init 0; such as files sync'd and
safe state to turn off server)

3. reboot (implements shutdown -r)

4. shutdown (shutdown -r now was recommended on a couple of sites.

Some web-sites said absolutely never user reboot. Since it just halts a
system and doesn't gracefully shut the system off. And then other
websites recommended using reboot since it really call shutdown -r now.

So, you shouldn't be surprised at my confusion.

Basic question, but what is the best answer. Since everywhere I looked
there was a note about how import it was to properly restart or shutdown a