The 3-2-1 Backup Rule, and Why It Still Holds Up
The rule predates both modern ransomware and cloud storage as most people use it. It still holds up, and the reason why has not changed.
The 3-2-1 backup↗ rule is decades old, it predates modern ransomware↗ entirely, and predates cloud storage as most people use it today. Despite that, it remains one of the most consistently recommended pieces of security advice around.
The rule itself: keep at least three total copies of important data, store them on at least two different types of storage media, and keep at least one copy somewhere genuinely separate from the others.
The "two different media types" clause matters because a single point of failure defeats the whole point of having multiple copies. If all three copies live on the same type of storage, one ransomware infection reaching all three because they're all constantly connected can wipe out every copy at once.
Modern ransomware makes the "offsite" clause the most important part of the rule today. It frequently searches an infected network specifically for connected backup drives and cloud-sync folders, encrypting them right alongside the primary data.
If you already have backups, the highest-value question isn't "do we have backups", it's "is at least one copy disconnected from our main network right now."