Question about backing up Zimbra

Hi,

I would like to know how you backup your zimbra infrastructure and how often do you take
snapshots of mailboxes.

I do 3 things:
* Backup of the ldap database daily.
* rsync /opt/zimbra on all servers ( --exclude 'store/' --exclude 'db/' --exclude 'index/' )
* Backup every account with the following :

###
/opt/zimbra/bin/zmmailbox -z -m $USERNAME gms >> $LOGFILE
/opt/zimbra/bin/zmmailbox -z -m $USERNAME getRestURL "//?fmt=tgz" > /backup/$USERNAME.tgz
/bin/chmod 644 /backup/$USERNAME.tgz
###

We want keep a year or more of mailbox in case something happens but we are little tight on space for backups.

I used to rsync the maildir's and that worked fine as every file were unique and we could keep them years without using using astronomic amount of space on tape backup.

Now every time I take a backup the file changes completely and it's in the range of 250gig per day.

We used to have over a year of backups before we moved to zimbra.

Any hints?

Charles