Confirm that your MacMini boot drive is specified as the target (drag it from the source list on the left into the 'Target' field).Confirm that your iMac boot drive ('Server HD'?) is specified as the source.Select your iMac's internal drive, and then click the 'Restore' tab.

Open the 'Disk Utility' program from the 'Utilities' menu.Boot the MacMini up into FireWire Target Disk Mode, and connect it to the iMac via FireWire.Boot the iMac up from the Mac OS X Server DVD.To restore the iMac drive onto the MacMini: Note: restoring via Disk Utility may require you to choose to erase the MacMini server's startup disk for it to be able to perform a block copy (which is the fastest restore option). However, this will retain all permissions, settings, trusted bindings, license, and other requirements from your previous install.

Performing a restore (block copy) of the data from one drive to another will require you to boot from another disk (the 10.6 server DVD?) to perform the copy. This can be accomplished by using the Disk Utility restore function. If you can afford the downtime, you will retain the most information and likely accomplish the fastest copy by performing a 'Restore' of the current server's drive onto the MacMini server's drive (this should work just fine being that both machines are currently running the same OS version).

Mac os x version 10.6 8 restore