LVM Setup in Linux

Linux lvm - Logical Volume Manager   LVM is a method of allocating hard drive space into logical volumes that can be easily resized instead of partitions,  particular, a volume manager can concatenate, stripe together or otherwise combine partitions into larger virtual ones that administrators can re-size or move, potentially without interrupting system use. 2. Create Partitions For this Linux lvm example you need an unpartitioned hard disk /dev/sdb. First you need to create physical volumes. To do this you need partitions or a whole disk. It is possible to run pvcreate command on /dev/sdb, but I prefer to use partitions and from partitions I later create physical volumes. Partition the Disk using partition tool FDISK  fdisk /dev/sdb Partitions are ready to use. 3. Create physical volumes Use the pvcreate command to create physical volumes. # pvcreate /dev/sdb1 # pvcreate /dev/sdb2 The pvdisplay command displays all physical volumes on your system. # pvdisplay Alternatively the following command should be used: # pvdisplay /dev/sdb1 4. Create Volume Group At this stage you need to create a virtual group which will serve as a container for your physical volumes. To create a virtual group with the name "mynew_vg" which will include /dev/sdb1 partition, you can issue the following command: # vgcreate mynew_vg /dev/sdb1 To include both partitions at once you can use this command: # vgcreate mynew_vg /dev/sdb1 /dev/sdb2 Feel free to add new physical volumes to a virtual group by using the vgextend command. # vgextend mynew_vg /dev/sdb2 5. Create Logical Volumes From your big cake (virtual group) you can cut pieces (logical volumes) which will be treated as a partitions for your linux system. To create a logical volume, named "vol01", with a size of 400 MB from the virtual group "mynew_vg" use the following command: create a logical volume of size 400 MB -L 400 create a logical volume of size 4 GB -L 4G # lvcreate -L 400 -n vol01 mynew_vg With a following example you will create a logical volume with a size of 1GB and with the name vol02: # lvcreate -L 1000 -n vol02 mynew_vg Note the free size in virtual group. 6. Create File system on logical volumes The logical volume is almost ready to use. All you need to do is to create a filesystem.: # mkfs.ext3 -m 0 /dev/mynew_vg/vol01 the -m option specifies the percentage reserved for the super-user, set this to 0 if you wish not to waste any space, the default is 5%.  7. Edit /etc/fstab Add an entry for your newly created logical volume into /etc/fstab 7.1. Mount logical volumes Before you mount do not forget to create a mount point. # mkdir /home/foobar 8. Extend logical volume The biggest advantage of logical volume manager is that you can extend your logical volumes any time you are running out of the space. To increase the size of a logical volume by another 800 MB you can run this command: # lvextend -L +800 /dev/mynew_vg/vol01