The new Mac Mini Server doesn't come with any installation media (DVD or USB flash drive). So if you replace the hard drive in your machine, or you have finished experimenting with Lion Server and are now ready to set it up properly from scratch, how do you do a clean install of Lion Server?

You can create a bootable installer for OS X Lion by following the instructions from sites like Egg Freckles, but how do you install the unique Lion Server parts? You could purchase them via the App Store but the Mac Mini Server came with Lion Server so you shouldn't have to pay (again).

If you use Recovery Mode (by holding cmd-r just after the startup chime) you can select Reinstall Mac OS X. On a 2011 Mac Mini Server this will actually install OS X Lion and Lion Server, although it doesn't mention Lion Server at all. You'll require an active internet connection to do this as it connects to Apple's servers, validates the machines eligibility, then proceeds to download the needed installer files. After downloading the files (taking anywhere from 40 minutes to 4+ hours depending on your internet connection speed), the machine will reboot and the installation starts in earnest. After the installation is complete and the machine restarts, you'll be back to a clean machine all ready for the initial setup process.

So, lets say you want to make a bootable Lion Server installer so you don't have to download the full 4GB the next time you need to do a clean (re)install.

For this you'll need:

• Mac Mini Server
• a firewire external drive (or USB), formatted as HFS+, preferably freshly erased
• active Internet connection
• your normal Mac

and either

• a blank DVD

or

• a USB flash drive (4GB minimum)

The steps

1. Restart your machine into Recovery Mode (cmd-r at the startup chime).
2. Select Reinstall Mac OS X.
3. Select your external drive as the destination.
4. Wait. But don't leave the machine unattended. Now comes the the tricky bit.
5. After the downloading is complete the machine will restart. At the chime we want to power off the Mini instead. If you don't the installation will continue and delete the temporary installer files we want to keep a copy of.
6. Disconnect the external drive and connect it to your main Mac.
7. On the external drive will be a folder called Mac OS X Install Data. It's owned by root and has permissions of 700 so you can't access it normally.
8. Jump into Terminal and change the owner to your normal account (this should all be on one line) sudo chown -R yourusername /Volumes/yourexternaldrive/Mac\ OS\ X\ Install\ Data/
9. Now we can open the Mac OS X Install Data folder. Amongst all the files is InstallESD.dmg. This is the Lion Server boot disc image and should be 3.94GB (the normal OS X Lion InstallESD.dmg is 3.74GB).
10. Launch Disk Utility and either burn this to a DVD or restore it to your USB flash drive.

Congrats. You should now have a bootable installer for Lion Server.

Test it out by booting the Mini from your new install disc/flash drive. You should boot to Recovery Mode and be presented with the normal options. Once you've confirmed it works you can throw away the Mac OS X Install Data folder on your external drive.

Nitty gritty

Looking through the install files, the major difference between the OS X Lion installer and the Lion Server installer are 2 extra packages in /Packages/

These are:

• Server.pkg
  Major components

  • Server.app

• ServerEssentials.pkg
  Major components

  • Xsan Admin.app
  • ClamAV
  • Dovecot
  • PostgreSQL
  • SpamAssassin
  • Server Manager
  • Podcast Producer
  • Calendar and Contacts
  • Webmail
  • Wiki

Otherwise the Lion Server InstallESD.dmg appears very similar to the OS X Lion version. There are differences in filesizes and modification date on the other packages but they are all quite minor.