Even though you're not going from 32-bit to 64-bit, I'd probably follow the same guide when making the transition to a new operating system. It requires a fresh Zimbra install and a manual restore of the messages, indexes, databases, LDAP info, etc. (
Network Edition: Moving from 32-bit to 64-bit Server - Zimbra :: Wiki)
A couple of questions:
- Do you have a spare machine for testing BEFORE you make the upgrade to 10.04 LTS? Or resources to try this in a virtual machine prior to a live transition?
I made the jump (several, actually) from a virtualized Ubuntu 6.06 LTS 32-bit running Zimbra 5.0.X to an Ubuntu 8.04 LTS 64-bit release running Zimbra 6.0.X (on an HP ProLiant 320 G5p). It took a decent amount of time for the transition, but it went pretty smooth. I followed the guide above from the wiki and it went well... The only difference was that I upgraded to 6.0.X AFTER moving the existing 5.0.X install. I also had the luxury of a bare, unused server... It would have been an uneasy/difficult move had I not been able to test EVERYTHING before performing the upgrade...
I'd recommend doing a full test in a lab environment (if possible) before proceeding. I'm not sure if the procedure you listed will work or not, but it's worth a try in a test environment. I found this wiki article (scroll all the way to the bottom) as well, which has detailed steps for moving servers/OS (from Fedora to Ubuntu):
Moving ZCS to New Server - Zimbra :: Wiki
But I also noticed it referenced the same 32-bit to 64-bit article [at least for migrating LDAP configuration]. Ignore the last part of that how-to if your hostname isn't changing... Hope this helps,
>JR