What do the LVM *create and *display commands do, and how are they paired?

Each layer has a matched pair: pvcreate/pvdisplay, vgcreate/vgdisplay, lvcreate/lvdisplay — one builds the layer, the other inspects it.

LVM's commands are wonderfully regular — the prefix names the layer (pv/vg/lv) and the suffix names the action:

pvcreate and vgcreate can take several devices at once to build a pool spanning disks:

pvcreate /dev/vdb1 /dev/vdb2
vgcreate vg01 /dev/vdb1 /dev/vdb2     # one VG across two disks

lvcreate is where you choose how to size the volume — by absolute size or by extent count:

lvcreate -n lv01 -L 128M vg01    # -L = by size (128 MiB)
lvcreate -n lv01 -l 32 vg01      # -l = by extent count (32 PEs)

Tip for remembering -L vs -l: capital -L is the big, human unit (Large — megabytes/gigabytes); lowercase -l counts the little extents. The finished LV is reachable at both /dev/vg01/lv01 and /dev/mapper/vg01-lv01.

Go deeper:

• lvm(8) man page — the full pv*/vg*/lv* command families and each create/display tool.