US-CERT states that all computer users, from home users to professional information security officers, should back up the critical data they have on their desktops, laptops, servers, and even mobile devices to protect it from loss or corruption. Saving just one backup file may not be enough to safeguard your information. To increase your chances of recovering lost or corrupted data, follow the 3-2-1 rule:
3 – Keep 3 copies of any important file: 1 primary and 2 backups.
2 – Keep the files on 2 different media types to protect against different types of hazards.
1 – Store 1 copy offsite (e.g., outside your home or business facility).