Keep in mind that this is documentation for an older version of Zimbra. At this time, my documentation for Zimbra 7.2.0 is the most recent.
When Zimbra 8 OSE comes out (hopefully on Ubuntu 12.04 LTS), I will make a new mail server and create a similar document. We are still not live with Zimbra yet which is why I would be doing another start-to-finish document. We just could not roll out a new email server at the same time that we were rolling out a new electronic medical records, billing and scheduling system. I should have some free time to start back on the Zimbra migration in the later part of August. Hopefully, Zimbra 8 for OSE will be available by then.
For the new documentation, I will be dividing up the partitions even more for better flexibility and security. You can see my progress on documenting an Ubuntu Server 12.04 LTS on my site. Much of it will translate over to a Zimbra installation.