I'm running Zimbra OSS 5.0.14 in a live environment right now and its working fine on its own. Over the weekend I tried twice to implement a backup LDAP server (we use LDAP for ALOT of things here) and had major problems. Each time it ended up taking down mail for an hour while I fixed it...
I tried to follow the LDAP Sync guide in the wiki here (LDAP - Zimbra :: Wiki). The guide says to setup another host and install Zimbra on it. You setup a few special settings during the install, and thats about it.
I got that working just fine ... but what I found was as soon as "ldap-copy.myhost.com" synced with "master-zimbra.myhost.com" a bunch of settings on "master-zimbra" changed. Things like the logHost setting changed to be "ldap-copy" instead of "master-zimbra" -- yet I had disabled all services on "ldap-copy" other than zimbra-ldap. This went un-noticed until I loged into the Admin WebUI and it complained about not being able to reach a host (connection refused). From there I tried to restart the "master-zimbra" services and Zimbra wouldnt even load up... the local LDAP database refused to start until I manually forced "ldap_bind_url" to be the "master-zimbra" hostname. I have no idea why it was empty, but the ldap start script wouldnt startup without it being something.
Nearly this exact thing happened twice in a row ... so I'm hesitant to try again, but we really need to get this running. Is there a way to setup zimbra-ldap without all the other stuff (mta, logger, etc)?