LVM

from command line

pvdisplay 

lvremove

lvdisplay

see the PV's

pvs
 PV         VG         Fmt  Attr PSize   PFree  
 /dev/sda  vg_1 lvm2 a--  930.82g      0 
 /dev/sdb  vg_1 lvm2 a--  931.31g 931.31g

 lvs -a -o +devices

add a disk to a PV

 vgextend vg_1 /dev/sdb
 Volume group "vg_1" successfully extended

remove a disk from PV

vgreduce vg_1 /dev/sdb
 Removed "/dev/sdb" from volume group "vg_1"

delete a PV

vgremove vg_1
Volume group "vg_1" successfully removed

create a mirror

lvcreate -L 931g vg_1 -m 1 vg_1