In the process of upgrading a Mac mini to be a server, I installed two SSDs to be configured as a RAID 1. One of the caveats to this approach is that a recovery partition is not supported when using a RAID as your boot volume. I had previously come across these instructions from Apple but looked them back up in order to install OS X. Even with my extremely fast fiber connection, it is still much slower to install from the recovery partition than it is from a local USB drive.

Update: This link was originally shared in 2014 but the guide has been updated by Apple for the latest versions of macOS as well so the title of this post has been updated to reflect that change.