There are several general features of all LVM CLI commands.

When sizes are required in a command line argument, units can always be specified explicitly. If you do not specify a unit, then a default is assumed, usually KB or MB. LVM CLI commands do not accept fractions.

Where commands take volume group or logical volume names as arguments, the full path name is optional. A logical volume called lvol0 in a volume group called vg0 can be specified as vg0/lvol0. Where a list of volume groups is required but is left empty, a list of all volume groups will be substituted. Where a list of logical volumes is required but a volume group is given, a list of all the logical volumes in that volume group will be substituted. For example, the lvdisplay vg0 command will display all the logical volumes in volume group vg0.

All LVM commands accept a -v argument, which can be entered multiple times to increase the output verbosity. For example, the following examples shows the default output of the lvcreate command.

# lvcreate -L 50MB new_vg
Rounding up size to full physical extent 52.00 MB
Logical volume “lvol0″ created

The following command shows the output of the lvcreate command with the -v argument.

# lvcreate -v -L 50MB new_vg
Finding volume group “new_vg”
Rounding up size to full physical extent 52.00 MB
Archiving volume group “new_vg” metadata (seqno 4).
Creating logical volume lvol0
Creating volume group backup “/etc/lvm/backup/new_vg” (seqno 5).
Found volume group “new_vg”
Creating new_vg-lvol0
Loading new_vg-lvol0 table
Resuming new_vg-lvol0 (253:2)
Clearing start of logical volume “lvol0″
Creating volume group backup “/etc/lvm/backup/new_vg” (seqno 5).
Logical volume “lvol0″ created

All LVM objects are referenced internally by a UUID, which is assigned when you create the object.

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