Minecraft: PS3 Edition does auto-save the world you are playing in on a regular basis so don't worry about losing your builds or survival mode progress. Instead, wait for the auto-save indicator to show up before quitting the game and always be sure to choose the "Exit without saving" option. PS Plus subscribers have the option to back up their game saves to the cloud. To do so, follow these steps: Go to Settings > [System Settings] > [Automatic Update] and set [Automatic Update] to [On] Under Game, select the game for which you want to automatically upload saved data, and then press the Triangle button. Select [Saved Data Auto-Upload] and set it to [On]. Now your Minecraft save will be backed up to the cloud every evening so that if it does get corrupted, you'll have a backup that can be copied down from Sony's servers. Non-PS Plus subscribers can backup their Minecraft saves as well by plugging a USB thumbdrive into their PS3 and following these steps. Go to Game > Saved Game Utility. Select Minecraft or any other game you want to back and press the Triangle button. Select [Copy] Choose the USB thumbdrive to copy the save file to. It's important to note that the USB method will require you to initiate the backup on your own regularly to ensure your work and progress are not lost. Source
