Coined by Peter Krogh, a commercial photographer who is also widely considered an expert in Digital Asset Management (The DAM Book), the 3-2-1 rule states that:
3 backup copies of your data should be maintained
Keeping three copies of your data (primary plus two backups) minimizes risk through probability. Imagine all your devices have the same characteristics, but no common failure causes. Now, imagine the probability of failure for each is 1/100. Maintaining primary data on one device offers a 1/100 chance of losing data. With a secondary device, the chance of losing data drops to 1/10,000 (1/100 x 1/100). With three backups, risk drops to a much more acceptable 1/1,000,000 (1/100 x 1/100 x 1/100).
2 independent storage mediums should be used
In the above scenario, there were no common failure causes across devices. But in the real world, when one disk fails, another is bound to follow suit. The 3-2-1 rule recommends using two types of storage to avoid such a scenario, for example, an internal hard drive plus a removable medium (tapes, external hard drives, USBs, etc.) or two internal hard drives in different locations.
1 backup copy should be stored offsite
Physical separation between copies is a necessity, and storing online backups in the cloud is an ideal solution. Not only do online data backup solutions add another layer of data protection, but a reliable data center is better equipped to handle threats such as fires, floods, or theft because they’re designed for them. Reputable data centers will have fire suppression systems, hurricane-rated structuring, environmental controls, raised flooring, biometric scanning, backup power supplies, and 24/7 surveillance. If you’re using Microsoft Office 365 and aren’t able to properly back it up, consider Apps4Rent, United State’s preferred Office 365 Backup Service provider.
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