I added a new disk using PVE (Proxmox) as a secondary IDE drive. Primary is 30GB. Running Ubuntu 14.04LTS (I know I should upgrade to 16, but I’m lazy)
Secondary drive is 400GB and I marked it NO Backup.
Adding a secondary HDD to linux is pretty easy.

List all of the drives
fdisk -l

In my case it showed that /dev/sdb didn’t have a partition table. That fact, added to the other fact I know I was using sda already, made my choice pretty easy. Don’t take my word for it and actually fact-check against your own equipment!

Create partition on the drive
fdisk /dev/sdb
n
p
1
Enter
w

“N” for new, “P” for primary partition, “1” for partition number, “w” to write table to disk and exit. Most of these are the defaults anyway, so hitting “enter” a bunch of times works.

Create the filesystem
mkfs.ext4 /dev/sdb1
Enter a bunch of times

Display the UUID of the new partition/drive
blkid /dev/sdb1
Should get something back like /dev/sdb1: UUID=”98d83dk-e4c3-38cd89-3830c0909903″ TYPE=”ext4″

Add to FSTAB
*note* Adam will laugh at my use of NANO, but I’m a creature of habit.
nano /etc/fstab
Add the UUID to the bottom:
#/dev/sdb1 /mnt/sdb ext4 defaults 0 0
UUID=98d83dk-e4c3-38cd89-3830c0909903 /mnt/sdb ext4 defaults 0 0

Make directory and Mount the drive
mkdir /mnt/sdb
mount -a

Profit!