I did a KDE workstation install. HDA is a 540mb drive set up
with / & 80mb swap. HDC is an empty drive (540mb) previously
formated with /home & /usr. Wiped drive clean. Just left
them formatted. Installer complained about not enough space
in/ . Went back & checked & the installer never checked HDC
for space & never put any partitions on it. After manually
partitioning drive it continued on fine.
This issue is resolved in the Red Hat Linux 6.2 installer which is able to make
use of multiple drives.