OS X Yosemite 10.10.1 on a Mac Mini Late 2012, 2.5 GHz, 16 GB. Server version 4 (14S333) 
Running the following services:
I moved my service data
and file shares to an external hard drive. When I format my startup hard drive, reinstall the operating system and server, what do I have to do to connect to the service data on my external hard drive? I imagine that I have to establish user accounts with the same credentials. 
Really, what I am after is that I'm trying to get Profile Manager to work right with my iOS devices.
And I have a wide variety of them (about 12 of them).
None of them work. They get a profile installation failure.
The research I've done seems to point to just reformat and reinstall.
But in doing so, I don't want to lose the service data. Any help you can provide, please...I need reassurance that when I reinstall everything, I'll be able to have access to the data store again. 
Thank you for your direction.
Running the following services:
- Caching
- Calendar
- Contacts
- File Sharing
- Profile Manager
- Time Machine
- DNS
- Open Directory
I moved my service data
Really, what I am after is that I'm trying to get Profile Manager to work right with my iOS devices.

Thank you for your direction.