August 10, 2011, 4:49 PM — Apple this week released a free utility called Lion Recovery Disk Assistant that provides an easy method for creating an official Lion Recovery drive from any 1GB (or larger) USB hard drive or thumb drive. You can download Lion Recovery Disk Assistant from Apple's Support site; it's about 1MB in size. Apple provides some brief instructions for using this utility, but those instructions don't give you the whole story—while the utility is indeed simple to use, there's a lot more you should know about creating and using a recovery drive.
Why you need a recovery drive
A must-have for any Mac user is some sort of bootable utility disc or drive—I call it an emergency drive, while Apple's taken to calling it a recovery drive. If your startup drive gives you trouble, you can boot from the recovery drive and in many cases perform any necessary repairs. With luck, you'll be back up and running in no time.
As I explained in our hands-on with Lion Recovery, when you install Lion (Mac OS X 10.7) on a Mac with a supported hard-drive configuration, the Lion installer creates a hidden, 650MB partition called Recovery HD. You can boot your Mac from Recovery HD by holding down Command-R at startup (or by choosing it from within Startup Manager, which you access by holding down Option at startup); you're then presented with options for verifying or repairing your normal startup drive and for reinstalling Lion. You can also browse the Web for troubleshooting info using Safari, and if worse comes to worst, you can even erase your startup drive and restore its contents from a Time Machine backup. Apple calls this feature Lion Recovery.
However, there are some considerable limitations to Lion Recovery. The most significant is that since Recovery HD is a partition of your Mac's startup drive, if that drive has hardware or partition-map problems, you may not even be able to boot from Recovery HD. Likewise, if you replace your Mac's hard drive, the new drive won't have a Recovery HD partition until you install Lion. So it's still a good idea to have a separate bootable utility disk.