This might seem like an odd question at first, but I was experimenting with an Amazon EC2 instance and forgot to partition an EBS drive under Linux.
I discovered I could directly format it with a filesystem and mount it without it even containing a partition table.
First, I was a little surprised I could actually do that. Then come to think of it, why not?
If the whole drive is going to be used for a filesystem anyway, should I partition it? Could there be a performance penalty in not doing so?