1. Multiple partitions on the same disk

LVM allows you to create PVs (physical volumes) out of almost any block device so, for example, the following are all valid commands and will work quite happily in an LVM environment:

# pvcreate /dev/sda1
# pvcreate /dev/sdf
# pvcreate /dev/hda8
# pvcreate /dev/hda6
# pvcreate /dev/md1
        

In a normal production system it is recommended that only one PV exists on a single real disk, for the following reasons:

However it may be desirable to do this for some reasons:

If you do have a disk with more than one partition and both of those partitions are in the same volume group, take care to specify which partitions are to be included in a logical volume when creating striped volumes.

The recommended method of partitioning a disk is to create a single partition that covers the whole disk. This avoids any nasty accidents with whole disk drive device nodes and prevents the kernel warning about unknown partition types at boot-up.