If one has access to a console server providing serial port access to a server, is it possible to reformat and re-install an OS on the server remotely?
Note that creating partitions under the existing OS and booting from an alternate partition is not an option.
Currently running RHEL6 on the server, if that makes a difference.
It entirely depends on your hardware and what can be done via the serial connection - and I hope you're not going to try to mount a DVD over serial: you've almost got to have a working NIC or some form of local media.
If you're running RH on Sun hardware, I bet there's a lot you can do. If you've got Intel server hardware from a top-tier vendor, look at their docs to see what you can do via serial after bootup before the OS loads from the disk; although IME, most Intel server vendors offer better remote management through their OOB management cards (Sup II, DRAC, iLo, etc) than via serial.