11.1. Initializing disks or disk partitions

Before you can use a disk or disk partition as a physical volume you will have to initialize it:

For entire disks:

• Run pvcreate on the disk:

  # pvcreate /dev/hdb

  This creates a volume group descriptor at the start of disk.

• If you get an error that LVM can't initialize a disk with a partition table on it, first make sure that the disk you are operating on is the correct one. If you are very sure that it is, run the following:

  	DANGEROUS
  	The following commands will destroy the partition table on the disk being operated on. Be very sure it is the correct disk.

  # dd if=/dev/zero of=/dev/diskname bs=1k count=1 # blockdev --rereadpt /dev/diskname

For partitions:

• When using LVM 1 on PCs with DOS partitions, set the partition type to 0x8e using fdisk or some other similar program. This step is unnecessary on PPC systems or when using LVM 2.

• Run pvcreate on the partition:

  # pvcreate /dev/hdb1

  This creates a volume group descriptor at the start of the /dev/hdb1 partition.