A NANDroid Backup consist in backing up a perfect mirror image of Android operation system. While some Backup methods only save some of your information a NANDroid backup will save literally everything, from your own personal data to the system files (widgets, ringtones, login, account settings, system settings to just mention a few).
Creating a good backup of your device is crucial, specially when experimenting with custom ROM’s and rooting your device. To get a better understanding of what a few minutes of work can safe you from, here are just some of the things a NANdroid security backup can safe you from:
Usually when backing up your device you need to reboot and enter recovery mode, something that can be a huge pain. Using a simple app like Online Nandroid it is possible to create the backup without rebooting, here is how: (This does require a rooted device)
The advantage of using this app is that you can keep using Android and don’t have to reboot to perform the backup