Linux Volume Manager

Set Up LVM:

1. Do fdisk to partition in the selected harddisk, let us take hdb for example
   

   fdisk /dev/hdb

   At the Linux fdisk command prompt,

   1. press n to create a new disk partition,
   2. press p to create a primary disk partition,
   3. press 1 to denote it as 1st disk partition,
   4. press ENTER twice to accept the default of 1st and last cylinder - to convert the whole secondary hard disk to a single disk partition,
   5. press t (will automatically select the only partition - partition 1) to change the default Linux partition type (0×83) to LVM partition type (0×8e),
   6. press L to list all the currently supported partition type,
   7. press 8e (as per the L listing) to change partition 1 to 8e, i.e. Linux LVM partition type,
   8. press p to display the secondary hard disk partition setup. Please take note that the first partition is denoted as /dev/hdb1 in Linux,
   9. press w to write the partition table and exit fdisk upon completion.

2. Next, this LVM command will create a LVM physical volume (PV) on a regular hard disk or partition:

   pvcreate /dev/hdb1
   

3. Now, another LVM command to create a LVM volume group (VG) called vg0 with a physical extent size (PE size) of 16MB:

   vgcreate -s 16M vg0 /dev/hdb1

   
   

4. Create a 400MB logical volume (LV) called lvol0 on volume group vg0:

   lvcreate -L 400M -n lvol0 vg0

   This lvcreate command will create a softlink /dev/vg0/lvol0 point to a correspondence block device file called /dev/mapper/vg0-lvol0.
   

5. The Linux LVM setup is almost done. Now is the time to format logical volume lvol0 to create a Red Hat Linux supported file system, i.e. EXT3 file system, with 1% reserved block count :

   mkfs -t ext3 -m 1 -v /dev/vg0/lvol0
   

6. Create a mount point before mounting the new EXT3 file system:

   mkdir /mnt/vfs
   

7. The last step of this LVM tutorial - mount the new EXT3 file system created on logical volume lvol0 of LVM to /mnt/vfs mount point:

   mount -t ext3 /dev/vg0/lvol0 /mnt/vfs

Monitoring:

vgdisplay vg0

To check or display volume group setting, such as physical size (PE Size), volume group name (VG name), maximum logical volumes (Max LV), maximum physical volume (Max PV), etc.

pvscan

To check or list all physical volumes (PV) created for volume group (VG) in the current system.

lvdisplay
To check or list all logical volumes

Extending :

vgextend vg0 /dev/hdb4

lvextend -L +800M(size) /dev/vg0/lvol0

resize2fs   /dev/vg0/lvol0

Removing :

lvremove  /dev/vg0/lvol0