If it's an external (I assume USB) drive, I would reformat it as Charlie says - then you don't run into problems long term.
Sounds like a huge drive, what are you planning to use it for ? If you want to use it as a complete SME backup, then if you are looking at disaster recovery, you need a device that can be supported by the re-install process - ie after rebuilding a new box/HDD and installing SME on clean HDD, you would want to use the restore from backup option when prompted on the first boot of the new machine.
Unless you want to read the disk on a windose machine and don't like using explore2FS.