The Joy of Penguins : Linux System Administration

Linux System Administration

Logical Volume Manager (LVM)

The next step is to create a Logical Volume from the Volume Group.
We can partition the volume group into logical volumes with the lvcreate command.
While hard disks are divided into blocks of data, logical volumes are divided into units called physical extents (PEs).
You'll have to know the number of available PEs before creating the logical volume.
This is done with the vgdisplay command using the new lvm-hdb volume group as the argument.

            sh-2.05b# vgdisplay lvm-hdb

            --- Volume group ---

            VG Name               lvm-hdb

            VG Access             read/write

            VG Status             available/resizable

            VG #                  0

            MAX LV                256

            Cur LV                0

            Open LV               0

            MAX LV Size           255.99 GB

            Max PV                256

            Cur PV                2

            Act PV                2

            VG Size               848 MB

            PE Size               4 MB

            Total PE              212

            Alloc PE / Size       0 / 0

            Free PE / Size       212 / 848 MB

            VG UUID               W7bgLB-lAFW-wtKi-wZET-jDJF-8VYD-snUaSZ

sh-2.05b#

As you can see, 212 PEs are available as free.
We can now use all 212 of them to create a logical volume named lvm0 from volume group lvm-hdb.

sh-2.05b# lvcreate -l 212 lvm-hdb -n lvm0

Logical volume "lvm0" created

sh-2.05b#

Prev Page 7 Next