Depending on the extent of your operation data can be saved on something as simple as a USB stick. For larger operations, you may need a disk storage system or may opt for cloud storage options as well. It is important to have this set up as an automatic measure as much as possible and for data to be saved to the backup at regular intervals. If you are allowing too much time to pass between backups then you are increasing your risk of major data loss when it is time to recover.
The best thing to do is to retain multiple backup copies. This allows you flexibility and assurance that you will be able to get data that is useful for moving forward from failure or attack. Backup and Recovery can be an expensive process. However, there are a number of free options for the software you can find online. If you want more than what free software has to offer, check out the services at DataOpts.