lvm logical volume paths

["Johan Booysen" <johan matrix-data co uk>]

hi all,
 
my apologies if this is a stupid question.  this relates to a Red Hat
Enterprise Linux Server 2.6.18-8.el5xen installation (i know bits and
pieces about linux, but have much to still learn).
 
why, when i cat fstab, do i get this:
 
# cat /etc/fstab
...
...
/dev/VolGroup00/data1   /data1                  ext3    defaults
1 2
/dev/VolGroup00/data2   /data2                  ext2    defaults
1 2
...
...
 
but when doing df i get "mapper" included in the output.
 
# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-data1
                      473G  198M  449G   1% /data1
/dev/mapper/VolGroup00-data2
                      473G   70M  449G   1% /data2
...

i'd appreciate your insights.