Rescue mode provides the ability to boot a small Fedora environment entirely from boot media or some other boot method instead of the system's hard drive. There may be times when you are unable to get Fedora running completely enough to access files on your system's hard drive. Using rescue mode, you can access the files stored on your system's hard drive, even if you cannot actually run Fedora from that hard drive. If you need to use rescue mode, try the following method:
Boot an x86, AMD64, or Intel 64 system from any installation medium, such as CD, DVD, USB, or PXE, and type linux rescue at the installation boot prompt. Refer to Chapter 18, Basic System Recovery for a more complete description of rescue mode.
For additional information, refer to the Fedora Deployment Guide.