Transferring domain from multi-site cpanel to another server

You might consider using the cpbackup-exclude.conf to prevent some directories from being backed up:
How to Exclude Files From Backups - cPanel Documentation

Say for instance you had a large directory of .pdf files, you could exclude that one directory from the "Full Website Backup", restore the backup you created on the new server and then move the .pdf directory some other way, rsync for example.

A really large account is best if backed up locally, moved, and then restored on the new server in my experience. Breaking it up into a couple of pieces even better if you can.

 

1. I've had a couple of these over the years, tough call. I was successful in making my cases, talking them into pruning the old mail. You can indeed exclude the email directory if needed though.

2. You can still exclude directories, compress and move them without shell access, certainly a bit more time consuming though.

3. Whats your time worth? This is a big account after all.

4. You can't. What you can do is back it up in parts though. Compress the /addon/ directory via File Manager Compress tool. Download and then upload to the new server and unpack via File manager. Or FXP from FTP to FTP if possible, probably not an option though. Backup any databases for it, and move them the same way. Depending on size you may need your Hosting providers assistance to restore those to MySQL for you. If it has any email accounts, you can move those manually as well. See this post by cPanelTristan for an example of how:
How to move website to another user - cPanel Forums

There are many other threads on these forums about this sort of thing, even this whole process you're trying to accomplish.

5. You could do a Full Website Backup, move it to public_html/ and wget the backup even, I suppose.

Very large accounts like this take some extra work, no doubt, you're not out of luck though. Depending on your experience and time to spare on this, you might give #3 some more thought. Or, think about explaining to the user that 20GB of mail is just plain crazy, you know?


GL!