WTF guys! The nightly upgrade to openldap-servers-2.3.30-2.fc6 decided to eat my database. I assume there is some compatibility issue as it moved all the files to an "rpmorig" subdirectory. No harm no foul there, but it then proceded to initialise a blank database and start that. So for the last 6 hours (befote I got wind of this) the incoming mail server has been tossing out every mail with "user unknown". I.e. a permanent error so those mail are forever gone. If you include an automatic update service, I expect to be able to use it. A downed server would be okay, a running blank database that causes lost mail is not. My problem is of course solved, but you really need to be more careful in the future with how your packets upgrade. At least when it comes to a critical component like this.
I copletelly aggree with you, unfortunatelly this bug is caused by wrong %preun/%postun in the previus release (openldap-servers-2.3.27-4), which were executed just now. See bug #230959 - it's the same bug, but for rawhide, so the version numbers are different. Just copy the database from /var/lib/ldap/rpmorig to /var/lib/ to restore your db. Updates _from_ openldap-servers-2.3.30-2.fc6 to newer version should be ok.
*** Bug 240136 has been marked as a duplicate of this bug. ***
*** Bug 240849 has been marked as a duplicate of this bug. ***
*** Bug 240925 has been marked as a duplicate of this bug. ***