It is possible to boot Linux in rescue mode using the installation media and bypassing the disk. During the rescue session, you can choose a network. Once the system is up, you will have access to the disk. Follow the below steps to boot in rescue mode:
1. Boot from the Linux Installation Media (this may require you to change the bios to boot from dvd).
2. Choose Rescue Mode by typing the following at the boot prompt and pressing [Enter]:
3. Choose the Language – Select desired language using arrow keys then press enter.
4. Choose Keyboard Type – Select desired keyboard type using arrow keys then press enter.
5. Network Interfaces – The network interfaces are unnecessary. Use arrow keys to highlight No then press enter.
6. Choose to mount the filesystem automatically. or choose to Skip mounting current system if you intend to fsck the disk (a filesystem that will be checked must be unmounted).
You are currently in Rescue Mode. If you allowed it, your root filesystem should be mounted as the /mnt/sysimage directory. For example, your /etc/fstab will be present at the /mnt/sysimage/etc/fstab location.
7. You can switch contexts so all the files will be available at their usual locations:
# chroot /mnt/sysimage # pwd / #
Although you are accessing the user-space files of your root filesystem, remember that you are still using the boot environment (such as the kernel and device inventory) from the rescue mode. Commands such as df or mount may not give the expected results. Leave the chroot context by using exit twice: once to exit the chroot and again to exit rescue mode and reboot:
# exit # exit