I suggest you mount the windows share on your Zimbra server and do an rsync.
Add the Windows share to your /etc/fstab:
Code:
//server/share /mnt/backup cifs credentials=/root/mount.c,rw 0 0
contents of /root/mount.c (chmod 600 this file!)
Code:
username=yourUserName
password=yourPassword
And rsync the lot:
Code:
rsync /opt/zimbra/backup /mnt/backup/
When using a linux box as the rsync target, use:
Code:
rsync -aH /opt/zimbra/backup /mnt/backup/
to keep permissions and hardlinks intact
(untested, no warranties, just a suggestion ;-) )