Lesson 4.2: Create and remove physical volumes

Flat partitions cannot be extended LVM (Logical Volume Manager) allows you to create logically grouped, dynamically expandable file systems on top of physical devices or partitions

PHYSICAL DISK --> PHYSICAL VOLUME --> VOLUME GROUP

	PV	VG	LV
Create	pvcreate	vgcreate	lvcreate
View Status	pvdisplay	vgdisplay	lvdisplay
Extend	N/A	vgextend	lvextend
Delete	N/A	vgremove	lvremove

Creating a PV using the entire disk or a partition

[root@sanjeeb ~]# lsblk 
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sr0          11:0    1    8G  0 rom  /run/media/root/CentOS-Stream-9-BaseOS-aarch64
nvme0n1     259:0    0   20G  0 disk 
├─nvme0n1p1 259:1    0  600M  0 part /boot/efi
├─nvme0n1p2 259:2    0    1G  0 part /boot
└─nvme0n1p3 259:3    0 18.4G  0 part 
  ├─cs-root 253:0    0 16.4G  0 lvm  /
  └─cs-swap 253:1    0    2G  0 lvm  [SWAP]
nvme0n2     259:4    0    5G  0 disk 
├─nvme0n2p1 259:5    0    1G  0 part /root/data1
└─nvme0n2p2 259:6    0    4G  0 part 
 
# Creating a PV for partition /dev/nvme0n2p2 
[root@sanjeeb ~]# pvcreate /dev/nvme0n2p2 
  Physical volume "/dev/nvme0n2p2" successfully created.
 
# Display the created PV 
[root@sanjeeb ~]# pvdisplay /dev/nvme0n2p2 
  "/dev/nvme0n2p2" is a new physical volume of "<4.00 GiB"
  --- NEW Physical volume ---
  PV Name               /dev/nvme0n2p2
  VG Name               
  PV Size               <4.00 GiB
  Allocatable           NO
  PE Size               0   
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               bEEVbN-bRRO-YQiI-D4IL-vPv0-8ldF-50qQCe

Removing a Physical Volume

# REMOVING A PV IF IT DOES'NT HAVE VG
[root@sanjeeb ~]# pvremove /dev/nvme0n2p2 
  Labels on physical volume "/dev/nvme0n2p2" successfully wiped.
 
# REMOVING A PV IF IT HAS VG
[root@sanjeeb ~]# pvremove /dev/nvme0n2p2 
  PV /dev/nvme0n2p2 is used by VG loanvg so please use vgreduce first.
  (If you are certain you need pvremove, then confirm by using --force twice.)
  /dev/nvme0n2p2: physical volume label not removed.
 
# Forcefully removing a PV
[root@sanjeeb ~]# pvremove -ff /dev/nvme0n2p2 
  WARNING: PV /dev/nvme0n2p2 is used by VG loanvg.
Really WIPE LABELS from physical volume "/dev/nvme0n2p2" of volume group "loanvg" [y/n]? y
  WARNING: Wiping physical volume label from /dev/nvme0n2p2 of volume group "loanvg".
  Labels on physical volume "/dev/nvme0n2p2" successfully wiped.
 
# Checking the removed VG
[root@sanjeeb ~]# vgs
  VG #PV #LV #SN Attr   VSize  VFree
  cs   1   2   0 wz--n- 18.41g    0