grokking kickstart partitioning

[Ryan Sawhill]

So I'm trying to edit a (fully-automated) kickstart file that I've
used to set up RHEL machines with no problems in the past. The problem
is that it makes some assumptions about how big the drive is supposed
to be, and though drive space is cheap, my laptop apparently doesn't
have enough and I'd like to have this accessible now as a VM running
for training purposes. So long story short, I'm hoping for a little
help in understanding the following part from the %pre section of the
ks, which I believe to be the culprit:

cat > /tmp/partitioning <<EOF

zerombr yes
clearpart --all
part /boot --start 1 --end 16 --ondisk sda
part /var/ftp/pub --start 17 --end 5017 --ondisk sda
part pv.1 --size=27648 --ondisk=sda
volgroup vg0 --pesize=32768 pv.1
logvol / --fstype ext3 --name=lv.root --vgname=vg0 --size=20480
logvol swap --fstype swap --name=lv.swap --vgname=vg0 --recommended
logvol /tmp --fstype ext3 --name=lv.tmp --vgname=vg0 --size=1024
--grow --maxsize=2048
logvol /var --fstype ext3 --name=lv.var --vgname=vg0 --size=2048
--grow --maxsize=2048
logvol /home --fstype ext3 --name=lv.home --vgname=vg0 --size=512
--grow --maxsize=1024
EOF

This of course is included with an '%include /tmp/partitioning' line
at the beginning of the ks. Parsing through this, I would expect the
part "pv.1 --size=27648" line to create a 27GB partition and it seems
that as long as the drive has more than that, this whole process
should be successful, but not so. Which leaves me confused, SOOO I'm
searching elsewhere and starting to play with this, but I thought I'd
through out a line in the meantime. :) Thanks to anyone who has some
insight!