How to create a Logical Volume Management

First create the physical disk to physical volume

#pvcreate /dev/sdb1 /dev/sdb2 (my case sdb is my hard drive)

or

#pvcreate /dev/sdb{1,2}

#pvdisplay [to display the physical volume]

#pvs ( to PV scan)

To create volume group

#vgcreate nameofvolume /dev/sdb{1,2}

e,g: #vgcreate intel /dev/sdb{1,2}

#vgdisplay

* TOTAL PE = total size / PE size { Physical Extend}

* TOTAL PE = 4 GB / 4MB = 1026

TO CREATE LV - Logical Volume

#lvcreate -L 1G -n newlogicalvolumename name of volumegroup

eg: #lvcreate -L 1G -n lv1 intel

-L size of logical volume

-n name of new logical volume

#lvdisplay [to display junks]

To cross check issue the below commands.

#vgdisplay

#pvdisplay

#lvcreate -L 1G -n lv2 intel [To create another logical volume]

Creating file system type

#mkfs.ext3 /dev/inte/lv1 [to make file system for LV1]

#mkfs.ext3 /dev/inte/lv2 [to make file system for LV2]

#mount /dev/intel/lv1

#df -h

you can notice the mount point

/dev/mapper/intel-lv1

Here "mapper" is the control device for LVM

#cd /dev/mapper

#ls

this will display the list of logical volumes

NOW WE WILL EXTEND ONE LV AND SHRINK ANOTHER LV

#lvextend -L +500M /dev/intel/lv1

-L length of size

*Now the volume will be increased, to increase we need to increase the FILE SYSTEM.

#resize2fs /dev/intel/lv1

now the whole partition is extended

* For shrinking first we need to shrink the filesystem and then shrink the Logical Volume

#umount /mountpoint

#resize2fs /dev/intel/lv2 500MB { need to specify the file system size after shrink}

#e2fsck -f /dev/intel/lv2

Then resize again to make successful

#resize2fs /dev/intel/lv2 500MB

#mount /dev/intel/lv2 /mountpoint

#df -h [now the file system is reduced]

To reduce the Logical Volume

#lvreduce -L -500MB /dev/intel/lv2

Now remove a Logical Volume

#umount /mountpoint1

#umount /mountpoint2

#lvremove /dev/intel/lv1

#lvremove /dev/intel/lv2

#lvdisplay ( nothing will be there ,, all removed )

#vgremove volumegroupname

#vgremove intel

#pvremove /dev/sdb1

#pvremove /dev/sdb2

Hope the above is useful to someone who have in middle of LVM configuring.