Apple provides several layers of security when it comes to your Lion installation. 1. There is a hidden partition on your hard drive if things go wrong (press Command-R during startup to access it). 2. Internet Recovery: This feature downloads Lion from an Apple server if the hard drive fails and there is no previous Lion installation available. 3. Create your own Recovery USB drive with Apple’s Lion Recovery Disk Assistant. 4. Restore from Time Machine Backup (if you have one). You can also create your own Lion restore solution, which doesn’t need Internet access.
While installing Mac OS Lion via Apple’s App Store is easy, reinstalling Lion on a clean hard drive is not. A new installation requires access to the App Store (or at least a Internet connection). So if your hard drive just died you are really in trouble. This is where a (home made) bootable Lion partition on a USB stick (8GB) comes as a real life saver. Here is how you create it: 1/ Locate the Lion installer package after downloading it from the App Store (before actually installing Lion). 2/ Right-click and open “Show Package Contents”. 3/ Look for the folder “ShareSupport” and locate the file “InstallESD.dmg”. 4/ Copy (don’t move) that file to another location and open Disk Utility or Carbon Copy Cloner. 5/ Using Disk Utility select “InstallESD.dmg” and do a “Restore” onto your freshly Mac formatted USB stick. (Remember to use that stick as a Lion boot disk only!) You now have a backup Lion system on your stick.