According to the Linux manpages you can add raw disks as well as partitions to a volume group.
In other documentation (RedHat, CentOS or openSUSE), all examples refer to adding partitions to the VG instead of raw disks. What is common (best) practice?
Best Answer
RHEL6 LVM Admin Guide
According to the RHEL 6 Logical Volume Administration Guide it's recommended that if you're going to use an entire drive as a physical volume in a LVM volume group, that you should still partition it:
excerpt from the guide "RHEL6 Logical Volume Manager Administration LVM Administrator Guide"
LVM Howto
Section 11.1. Initializing disks or disk partitions of the LVM Howto states as follows:
excerpt from the LVM Howto
Conclusions
These are the primary sources I would trust in determining whether you should format a single partition on a HDD prior to adding it as a physical volume or not. As other answers have indicated (and comments) you wouldn't be wrong in just adding the entire drive without a partition.
To me I liken it to driving in my car with my seat-belt on. If you never get in an accident then the seat-belt has served no purpose, but if I ever do get in an accident I"m sure glad I was wearing it.
Follow-up #1 (To @Joel's comments)
I thought the above 2 guides were 2 pretty good reasons. They're both official guides, one from RH the other a Howto put together by the LVM team.
Here's another reason. By not partitioning the HDD, no ID is being explicitly set on the HDD to clearly identify how it's being used.
As an administrator of systems, it's much more obvious to myself and others the intent of how this particular drive is being used vs. without the 8e.
I appreciate what you're saying @Joel, I too worked at a fortune 500 company where we had 100's of Linux deployments in both desktop/server physical/virtual deployments, as well as in large storage deployments, so I get what you're saying.