If this is an external (i.e., USB) drive, and there is the slightest chance that it could get plugged into a Windows PC, I would recommend a small
(32-128 MB) FAT partition at the beginning. Otherwise, when Windows see the device, but realizes it can't read it, it will offer to "fix" it, and if the user haplessly clicks OK, it will format the (ext4, or whatever) partition and POOF!
, there goes your data.
If there is a small FAT (or VFAT) partition at the beginning, Windows will mount it, and ignore the rest of the drive.
Just some extra info to keep in mind.
Fixed spelling / grammar