I'm looking to move our Zimbra NE installation out onto a new dedicated server and in the process I would like to go from CentOS 5 64bit to CentOS 6 64bit. Once I'm running on CentOS 6 I will then upgrade to ZCS 8 and I'd also like to change the primary hostname of the server as well, though keeping the users with the same primary e-mail domain.
1) What's required to go from CentOS 5 to CentOS 6?
Is it as simple as running a full backup, copying over to the new server, making sure the new server has the same hostname, installing the same build of ZCS 7, then restoring the backup onto the new server?
Both are 64bit and I've read that going from 32bit to 64bit requires a bit more work.
2) Is it possible to change the primary ZCS hostname of a running installation?
3) Then can I run Zimbra Proxy so the previous hostname can still be used to access ZCS? e.g.: https://webmail.olddomain.com
Is it possible to proxy the IMAP, SMTP and SMTP-submission hostnames as well?