I had some grief installing Zimbra on basic "server-like installation" system (CentOS 4.2). The installation manual for Zimbra says "accept default setup answers" for OS installation. In short, it means full desktop installation, with GNOME, OpenOffice and bunch of other crap nobody sane really wants to have installed on production server machine. My basic installation is around 500MB in size (usually around 150 packages). Desktop install is around 4GB in size (almost 600 packages).
For trying out Zimbra on my test box, the desktop install is tollerable. However, there is no way "desktop install" box would be put into production at my site... Even default "server install" has so much crap on it that I wouldn't be happy running such machine in production.
My "basic server installation" is done like this (from ks.cfg file):
What else is really needed by Zimbra? I'm sure it doesn't need all of those additional 500 packages from desktop installation.
# Install only Core packages, do not install garbage from Base package group
# Usefull stuff from Base
# Zimbra dependencies