Volume Management

lsscsi <-- to get list of devices

[0:0:0:0] disk ATA VBOX HARDDISK 1.0 /dev/sda
[0:0:1:0] disk ATA VBOX HARDDISK 1.0 /dev/sdb
[1:0:0:0] disk ATA VBOX HARDDISK 1.0 /dev/sdc
[1:0:1:0] disk ATA VBOX HARDDISK 1.0 /dev/sdd

fdisk -l /dev/sdc <-- verify size of your new device

Disk /dev/sdc: 36 GiB, 38654705664 bytes, 75497472 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

vgcreate [vgname] /dev/sdc <-- which vg you want to add the new disk

lvcreate -L [total combined size]G --name [lvname] [vgname]

mkfs -t btrfs /dev/vgname/lvname <-- For new volume

OR

vgextend (vgname) /dev/sdc1

lvextend --size (size)G /dev/path/(vgname)/(lvname)

OR

lvextend --extents +100%FREE /dev/path/(vgname)/(lvname)

reszie2fs /dev/path/(vgname)/(lvname)

OR

xfs_growfs /mount_point as the case may be.