How to make LVM in Linux

A) create partition

Note: you better know how to create partition so here we have already created two partitions named /dev/sda1 and /dev/sdb1

Step 1:- physical volume create 

A)   [root@desktop3 Desktop]# pvcreate   /dev/sda1
    [root@desktop3 Desktop]#  pvcreate   /dev/sdb1

OR

   [root@desktop3 Desktop]# pvcreate  /dev/sda1  /dev/sdb1


B) physical volume display 

  [root@desktop3 Desktop]#  pvdisplay   /dev/sda1
  [root@desktop3 Desktop]#  pvdisplay   /dev/sda1 /dev/sdb1
 
OR
 
  [root@desktop3 Desktop]# pvs
  PV         VG   Fmt  Attr PSize   PFree 
  /dev/sda1  vol0 lvm2 a--   58.56g   1.75g
  /dev/sdb1       lvm2 a--  400.00m 400.00m



Note: There are some advanced commands for physical volume management so you doesn't need to follow the steps but if you know about these commands then you can use.

OR to scan physical
========

[root@desktop3 Desktop]# pvscan
  PV /dev/sda1  VG vol0            lvm2 [58.56 GiB / 1.75 GiB free]
  PV /dev/sdb1                      lvm2 [400.00 MiB]

check pv metadata

[root@desktop3 Desktop]# pvck  /dev/sda1
  Found label on /dev/sda1, sector 1, type=LVM2 001
  Found text metadata area: offset=4096, size=1044480

Enable / disable allocation of physical extent
!) for disable

[root@desktop3 Desktop]# pvchange -x n  /dev/sda1
  Allocatability not supported by orphan lvm2 format PV /dev/sda6
  0 physical volumes changed / 1 physical volume not changed

!!) For enable

[root@desktop3 Desktop]# pvchange -x y  /dev/sda6
  Allocatability not supported by orphan lvm2 format PV /dev/sda6
  0 physical volumes changed / 1 physical volume not changed
change size of physical volume

[root@desktop3 Desktop]# pvresize --setphysicalvolumesize 1G /dev/sda1
  WARNING: /dev/sda1: Overriding real size. You could lose data.
  Physical volume "/dev/sda1" changed
  1 physical volume(s) resized / 0 physical volume(s) not resized


[root@desktop3 Desktop]# pvdisplay  /dev/sda1
  --- Physical volume ---
  PV Name               /dev/sda1
  VG Name               vg1
  PV Size               1023.00 MiB / not usable 3.00 MiB
  Allocatable           yes
  PE Size               4.00 MiB
  Total PE              255
  Free PE               255
  Allocated PE          0
  PV UUID               gQFfaj-PFCR-Vagd-mxj1-31Yb-pdkF-hDJWuV

Step 2:-  volume group create 
[root@desktop3 Desktop]# vgcreate  mystorage  /dev/sda1  /dev/sdb1
 [root@desktop3 Desktop]#   vgdisplay  mystorage

Step 3:-   lvm create 

[root@desktop3 Desktop]# lvcreate    --name  mylvm1  --size  800M  mystorage
 [root@desktop3 Desktop]# lvdisplay   /dev/mystorage/mylvm1


B)  format partition

[root@desktop3 Desktop]# mkfs.ext4   /dev/mystorage/mylvm1

C)  mount partition
[root@desktop3 Desktop]# mkdir  /media/myst
[root@desktop3 Desktop]# mount  /dev/mystorage/mylvm1 /media/myst


Lvm Extend:-




[root@desktop3 Desktop]# lvextend   --size  +200M  /dev/mystorage/mylvm1
 [root@desktop3 Desktop]# resize2fs   /dev/mystorage/mylvm1

Note: resize2fs  command will work till filesystem (ext2,3,4)

Note:  IF  you have formted  your LVM with XFS  then

[root@desktop3 Desktop]# lvextend   --size  +200M  /dev/mystorage/mylvm1
 [root@desktop3 Desktop]# xfs_growfs    /dev/mystorage/mylvm1

LVM  reduce (ext2,3,4) :-



To reduce size of LVM follow below given steps:

1.  unmount  the LVm

 [root@desktop3 Desktop]# umount  /media/myst/

2.  scan LVM

[root@desktop3 Desktop]# e2fsck   -f   /dev/mystorage/mylvm1

3. resize LVM

[root@desktop3 Desktop]# resize2fs   /dev/mystorage/mylvm1   300M

4.  reduce LVM

[root@desktop3 Desktop]# lvreduce  --size  300M  /dev/mystorage/mylvm1

5.  mount LVM

 [root@desktop3 Desktop]# mount  /dev/mystorage/mylvm1  /media/myst/