I don't see how generally knowing if the server is physical or virtual makes a difference on the patching of the OS. You might need to know the firmware level for a physical server or the virtual host version I suppose, but that's probably quite specialised research.
Patches for RHEL are generally banded into three areas:-
- Security fixes - critical updates
- Bug fixes - corrections for errors that might be causing you a problem
- Enhancements - updates to process or code to either make it run more efficiently or providing more function/output/options.
You should be very active patching at least the Security fixes. You may choose (or not) to apply the others, but usually a
yum update will pick up everything applicable for your server. If you do this, make sure you are able to boot again afterwards and that there is space available in
/boot in case it triggers a kernel rebuild in the boot.
I hope that this helps,
Robin