LVM Extend or Reduce Using e2fsck resize2fs lvextend lvreduce Command

After LVM creation if we need to extended or reduce we can do that using e2fsck, lvreduce,lvextend.
First we need to create Logical Volume Manager LVM CREATION TUTORIAL.

Logical Volume Extend & Logical Volume Reduce
1)LVM is created by layer by layer like
Physical Disk -> volume Group -> LVM - > File System.
2) So if we want to extend LVM.
First extend the Lvm then File system.
3)if we want to reduce the LVM.
First reduce the File system then LVM.
That is correct Format.

Logical Volume Extend	Logical Volume Reduce
Lvmextend - > resize2fs	Resize2fs -> lvreduce
Extend & Reduce we have to follow sequence.

Pvcreate	Vgcreate		Lvcreate
Pvs (report /Information)	Vgs		Lvs
Pvdisplay	Vgdisplay		Lvdisplay
Pvscan	Vgscan		Lvscan
Pvremove	Vgremove		Lvremove
	Vgextend		Lvexend
	Vgreduce		Lvreduce
ext2online		Resize ex2 file system (Used for RHEL Version 4 )
resize2fs		Resize ext2 & ext3 file system. ( but it is apply for ext4 also).
#System-config-lvm		Used to configure Logical volume
1)#mount    /dev/VOLUME_GROUP/LOGICAL_VOLUME /Mount-pt		How to mount the logical volume

Difference between RAID and LVM

RAID	LVM
1)Designed for storage,Data Backup , fault-tolerance(redundancy). 2)RAID is (storage technology) that combines multiple disk drive components into logical UNIT. In other words  physical grouping of disk to create the logical representation of one disk.	1)Create & Extended  logical representation of the file system. 2)depends on the requirement to shrink or grow the file system.
Striping mirroring stripping with parity.

 Check The File System
e2fsck comman is used to check the ext2 and ext3 file system.
This command is normally used when we reduce or extended file system. it will check the inodes, directory structure,
 directory connectivity, and Rerference counts.
-f it will check the filesyste with force.
[rhel5@bash /]# e2fsck -f /dev/vgo/lv0
e2fsck 1.39 (29-May-2006)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
/dev/vg1/data: 11/3072 files (9.1% non-contiguous), 1531/12288 blocks

Lvextend lvreduce Syntax
#[lvexted|lvreduce] -L [SIZE] [DEVICEPATH] 
 Resize2fs Syntax 
#resize2fs [PATH] [SIZE]
Vgextend Vgreduce Syntax
#[vgextend|vgreduce]  [volume_Group] [Device_Path]
Extend the Volume Group Logical Volume with New Disk

Create New Physical Partition

#fdisk /dev/sdb

Make the File system in ext3

#mkfs.ext3 /dev/sdb1

Create the physical Volume

#pvcreate /dev/sdb1

Extend the Volume Group

#vgextend VolGroup00 /dev/sdb1

After add the partition using vgdisplay and lvdisply check whether partition is added or not.

Extend the LVM with New Physical Volume

#lvextend /dev/vg1/lv0 /dev/sdb1

NOTE : Once we extend and reduce the lvm while mounting check the file system size using df -h. it will show the latest file system size, if it is still show the old one. reason is we need to initiate the e2fsck -f /device/path command and resize2fs once did that. it will update the latest file system utilization. Useful Links:

http://www.linuxhelp.in/2010/04/logical-volume-managementlvm-every.html

http://www.markus-gattol.name/misc/mm/si/content/lvm_df_3.jpg

http://www.sureshkumarpakalapati.in/2010/08/lvm-commonly-asked-interview-questions.html