This assumes you are familiar with LVM (Logical Volume Manager). If not, check out my article Getting Started with LVM (Logical Volume Manager).

Before creating an LVM physical volume, the parition must first be configured with type Linux LVM. This can be accomplished with fdisk, gdisk, or parted. Here are the steps on how to set /dev/sda3 to type Linux LVM using parted.

parted -s /dev/sda set 3 lvm on

Let's say you have two storaged devices where /dev/sda3 and /dev/sdb1 are configured as LVM partitions.

The pvcreate command can be used to create LVM physical volumes. 

pvcreate /dev/sdb1

The following should be displayed.

Physical volume "/dev/sdb1" successfully created.

The pvdisplay command can be used to verify that /dev/sdb1 was added as an LVM physical volume.

--- NEW Physical volume ---
PV Name               /dev/sdb1
VG Name
PV Size               <100.00 GiB
Allocatable           NO
PE Size               0
Total PE              0
Free PE               0
Allocated PE          0
PV UUID               qIJr3I-uokW-qIRJ-Mi9a-SmIp-2DYN-XwxUDf

Next, create a volume group.