Some notes about wmdiskmon and the LVMs:

I believe RAID and LVMs are not only for Servers with HDs in RAIDs like SANs. In some cases a servers run without LVMs, for example my Virtualization server runs KVM (Linux native) and I create VMs on the LVM, and VMs could be installed without LVM.

To run to check just partitions:
# df -h
# mount
# nano /etc/fstab

IE:
# df -h
Filesystem                 Size  Used Avail Use% Mounted on
rootfs                     145G   18G  120G  13% /
udev                        10M     0   10M   0% /dev
tmpfs                       88M  716K   87M   1% /run
/dev/mapper/ProLiant-root  145G   18G  120G  13% /
tmpfs                      5.0M     0  5.0M   0% /run/lock
tmpfs                      175M   72K  175M   1% /run/shm
/dev/sda1                  228M   19M  198M   9% /boot

New tool to check LVM:
# pvs
Output:
PV         VG       Fmt  Attr PSize   PFree
/dev/dm-0  ProLiant lvm2 a--  148.80g    0 

More options to LVM:
This is relatively easy. Use lvdisplay to show logical volumes, vgdisplay to show volume groups (including free space available) and pvdisplay to show physical volumes.
You should get all the data you need from those three commands, albeit with some work to figure out what all the various bits of data mean.

# vgs
# lvs

pvs, vgs and lvs are convenient easy-to-read alternatives to pvdisplay, vgdisplay and lvdisplay if you only need a summary.
The "maps" option is what you are after. This works at the lv level as well as pv.
So if you want to see what room an LV is taking up on a volume, do:
# lvdisplay -m <volumegroupname>
If you want to see the usage of PVs, do:
#pvdisplay -m

Reference:
Web: http://serverfault.com/questions/262541/how-to-display-used-devices-free-space-when-using-lvm
File: LVM stats commands.pdf.