Managing LVM (+swap)

 
Physical devices ; divides the physical volume into physical extents (PEs)
Physical volumes(PVs)  ; combined size,
Volume groups (VGs)
Logical volumes(LVs)


Creating Logical Volumes:
#pvcreate /dev/vdb2 /dev/vdb1
#vgcreate vg01 /dev/vdb2 /dev/vdb1
#lvcreate -n lv01 -L 700M vg01 ; -L = -size
#mkfs -t xfs /dev/vg01/lv01
#mkdir /mnt/data

#vi /etc/fstab
/dev/vg01/lv01 /mnt/data xfs defaults 1 2
systemctl daemon-reload
#mount /mnt/data
umount /mnt/data

lvremove /dev/vg01/lv01
vgremove vg01
pvremove /dev/vdb2 /dev/vdb1

pvdisplay /dev/vdb1
vgdisplay vg01
lvdisplay /dev/vg01/lv01

Extending a Volume Group  :
parted -s /dev/vdb mkpart primary 1027MiB 1539MiB
parted -s /dev/vdb set 3 lvm on  (set type to Linux LVM)
pvcreate /dev/vdb3

vgextend vg01 /dev/vdb3
vgdisplay vg01

Reducing a Volume Group
(back up data stored on all LVs in the VG)
pvmove /dev/vdb3
vgreduce vg01 /dev/vdb3

Extending a Logical Volume and XFS/EXT4 File System :
vgdisplay vg01 (check VG have space available)
lvextend -L +300M /dev/vg01/lv01
xfs_growfs /mnt/data   :  for xfs (mountpoint name)
resize2fs /dev/vg01/lv01   :  for ext4 (lv name)

df -h /mountpoint

lvextend -l 128 : Resize the logical volume to exactly 128 extents in size (128 PEs x 4 MiB.
lvextend -l +128 : Add 128 extents to the current size of the logical volume.
lvextend -L 128M  : Resize the logical volume to exactly 128 MiB.
lvextend -L +128M : Add 128 MiB to the current size of the logical volume.
lvextend -l +50%FREE : Add 50 percent of the current free space in the VG to the LV.


Extend a logical volume and swap space  :
vgdisplay vgname : check vg free space
swapoff -v /dev/vgname/lvname
lvextend -l +extents /dev/vgname/lvname
mkswap /dev/vgname/lvname
swapon -va /dev/vgname/lvname


Your system must have enough free memory or swap space to accept anything that
needs to page in when the swap space on the logical volume is deactivated.