Throw together a quick LVM config for dumping the device mapper table

lvm-cheat.sh

#!/bin/bash

# create empty volume files
truncate --size 256M /a
truncate --size 256M /b

# attach them to loopback devices
deva=$(losetup --find)
losetup $deva /a
devb=$(losetup --find)
losetup $devb /b

# format as LVM physical volumes
pvcreate $deva
pvcreate $devb

# create the volume group
vgcreate test $deva $devb

# create a mirrored (RAID1) logical volume with an in-memory replication log
lvcreate --extents 1 --mirrors 1 --corelog --name lv_derp test

dmsetup table /dev/mapper/test-lv_derp
# 0 8192 mirror core 1 1024 2 253:0 0 253:1 0 1 handle_errors