The most simple method is to backup your /opt/zimbra directory, wipe out your current filesystem and replace it with ext3, install a new copy (the same release in the new /opt directory ) of Zimbra, restore the /opt/zimbra directory over the recently installed one and reinstall zimbra again. Slightly long winded but it works fine.
Use the following rsync command to copy and restore and keep the corret file permissions:
obviously file location for your bacup is your preference.
# rsync backup
rsync -avrlHKpogDt /opt/zimbra/ /data/backup/zimbra
# rsync restore
rsync -avrlHKpogDt /data/backup/zimbra /opt/zimbra