What is the impact of destroying and re-creating from scratch the Open Directory Master?

Question

In order to try and solve some nasty issues hat I have since upgrading to OS X Server 3,0 I am considering completely destroying my OD Master and re-creating the users and groups from scratch. Before doing so (of course I will have multiple backups) I would like to understand:
1.   When re-creating the users and groups is it sufficient to use the same ‘Unix’ groupid and userid numbers or do I also need to use the original GeneratedUIDs (is that even possible)? Are there any other aspects of the users/groups that I need to be sure to preserve?
2.   Will there be any impact to services and their data from doing this? Specifically, I have users with data in Mail, Calendar, Contacts and the WiKi. Will they still be able to access their data after the OD destroy/re-create or is that data somehow tied to more than just the username (e.g. does it use the user/group UUID or indeed any other UUID from OD)?
3.   Will there be any impact to OS X clients bound to the OD? Should I unbind them before destroying and re-bind them afterwards? Will there be any negative impact on the network users who log in via these systems (they all have ‘mobile’ accounts which do *not* sync to the server - all their data is local to the client)?
Thanks in advance for any advice especially from anyone who has gone through this process.
Chris

Answer 1

Hi Rob,
I have solevd my issue and I did not need to destroy / re-create the Open Directory. See my post here https://discussions.apple.com/thread/5785838 for all the gory details. The long and the short of it was that my problems all came from a point in the past when I changed the hostname of my server after I had created the Open Directory master. Seems like that is a very bad idea! Based on what I found it seems liek any small flaw in DNS forward and reverse name resolution can also cause similar issues. I don't knwo if either of thsoe may apply to your situation?
As part of troubleshooting my issue I actually created a 'replica' of my server setup on another machine includingthe OD and associated users and groups. What I found was that many services (certainly mail, calendar and contacts) depend completely on the OD users and groups UUIDS. So if you wish to preserve user's data across an OD destroy and re-create it is vital that you carefully note for each group its Unix GID and its OD UUID and for each user their Unix uid, primary group id and UUID. When you are re-creating your OD master, as you create each group, use Directory editor to change its UUID to the original value. Similarly for Users. If you don't then users will no longer have access to any existign Mail, Contacts or Calendar data afterwards!
HTH,
Chris