Encrypting 10.7 non-boot volumes without erasing them

In addition to using FileVault 2 to encrypt your boot partition, it’s possible to encrypt your non-boot storage on 10.7 using the same CoreStorage-based encryption. Apple provided a way to do this via Disk Utility, where you would need to erase the drive and have the new volume be set up as an encrypted volume.

It is also possible to encrypt the drive without erasing it first from the command line. This allows your existing data to stay on your drive while the drive is being encrypted. See below the jump for the procedure.