I have a chance of buying thanks to a friend a 3TB hard drive but I have heard a problem about passing the 2TB barrier. Will I be able to boot form it or use it correctly (detected correctly) or is it recommended I use it as a second hard drive to save files but not as the main bootable drive.
Yes, it does. If you are still booting in a bios based machine and not an EFI one, you need to create a 1MB bios_grub partition when installing ( assuming you are going to boot from this drive ). The partition is required to install the bios based grub on a GPT partitioned disk.