Apologies in advance if this topic has been addressed out here (I could not find any threads for my migration scenario):

We are currently running Zimbra Enterprise version 7.13 on a Redhat 5.XX, 32 bit server. We are interested in getting up to date with current specs now that VMWare is running the Zimbra show. We wish to upgrade to Version 8 running on Ubuntu LTS 12.0.4, 64 Bit server.

I cannot find any detailed procedures for this upgrade process. I get the basic steps that there is no direct upgrade, and that I will essentially need to back up our current Zimbra build and data, build a new server on the new OS, re-install version 7.13, restore my data, then upgrade to 8 however, I really need more detail on this process than just the "eyeball it" procedures.

Specifically I want to know what requisite files/directories/data needs to be backed up? I also want to know what the proper restore process is for when we re-install 7.13 to the new server (again, what files/directories/data gets restored, in what order, what config. files need to be modified - if any, etc.), then the upgrade process to version 8.

We tried the "eye ball it" upgrade approach over the summer and we needed to totally abort it because it failed miserably in the middle of the process.