Dagar, if you're FOSS & have a relatively low number of users/store size, manually walk through the rsync processes listed in
A_Simple_Shell_Script_Method - Open Source Edition Backup Procedure - Zimbra :: Wiki (other FOSS methods are listed on that page as well).
NE's should use
zmbackup to take a full. Don't just use the admin console to create one - I don't remember what version it got fixed in, but the admin console invoke used to excludes a few things that might be handy to have later
Disk images/ghosts/LVM snapshots/rsync's are also good methods of course - just be sure to have a backup, you'll thank yourself for doing it someday
