==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.8.7, 0.9.0,  0.9.2
- Linux/BSD distribution name and version: Ubuntu 14.04LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx):Nginx
- Manage mail accounts with iRedAdmin-Pro? Yes
- Related log if you're reporting an issue:
====

I need to upgrade, move and merge multiple iRedmail servers to a single iRedmail server running the latest 0.9.4 version. Each existing iRedmail server hosts a number of different mail domains.

I have studied the upgrade and move tutorials and I believe I am comfortable with the general upgrade and move processes.

I plan to upgrade all the existing iRedmail servers to the latest version and then I want to migrate and consolidate all the mail domains and mailboxes onto a single new server.

Specific questions related to the consolidation of mail servers:

1.  Can I just export the vmail database on each server and import into MySQL on the new server, one after the other?

2.  Can I copy all the folders under /var/vmail from the different servers to /var/vmail on the new server, one after the other?

My concern is that I may overwrite something by repeating the import and copy process with files and mail folders coming from different servers.

Are there any issues I need to look out for?