Question: So I have a server that has a few harddrives in it, all formatted and mounted. However I'm told there is another drive attached to it. How do I find out what drives are attached? How do I find out the device filename for this new drive (that's not mounted)

Answer: 
`fdisk -l`​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​
fdisk -l 

dmesg

/var/log/message..