Rsync is not, and never has been, a valid way of backing up the LDAP server. The fact that this is referenced in numerous location is a mistake that should be corrected. Using rsync is the wrong thing to do in any circumstance, regardless of the 80GB copying issue. In any case, there is nothing holding you to using the 80GB maximum data size. This is why there is a localconfig key in ZCS 8 that allows you to adjust the maxsize, and this is why that key is documented on the Zimbra Wiki for OpenLDAP tuning in ZCS 8.
RSYNC is a perfectly reasonable way to backup a system that has no open DBs or files and that is how it has been used. Things change and that is often good, so long as the change continues to help. The idea of dealing better with the LDAP DB is a great idea, but why provision 80GB for all DBs and adversely affect other supporting processes that work in a wider application when there is no need.
As noted above -- We needed some maximum that we could ensure any migration would allow for. There are certainly installations with multi-gigabyte LDAP databases. I have a 16GB one from a customer I use for testing internally. I'm fairly positive no one has an 80GB size database.
That last point is the one I am trying to understand, is there a clear need to provision 80GB of DB space for something that is usually no where near that size. Is it not better to fit the purpose as needed and provision more appropriate sizes for the DB and avoid the hassle. I can't answer that which is why I wanted Quanah to explain the drive to provision the 80GB not say 1GB or 500MB. Can you explain that Quanah?