Legacy Shared Domains
You might encounter legacy shared NetInfo domains. This is not particularly likely, particularly in any recent Mac OS X Server infrastructure because Apple has made it very difficult (though not impossible) to create new shared NetInfo domains. However, if an older server has been in service since an earlier version of Mac OS X Server, or if a new server has been put into service by restoring it from a backup or drive copy of an older server, there is the possibility that you might come across a NetInfo domain.
Apple has provided tools to migrate data from a shared NetInfo domain to an OpenLDAP domain. If you encounter a situation in which there is a legacy NetInfo domain, your best course of action at this point is to develop a migration strategy for the server and network. However, as with any critical service migration, you should have a backup strategy planned in the event of failure.