GuideManaged IT
The 3-2-1 backup rule, explained
By Inara Crest Engineering 1 min read
Three copies, two types of storage, one off site — and at least one copy that ransomware cannot reach.
The 3-2-1 rule is a simple way to make sure no single failure, theft or attack destroys your data.
1. Three copies
Keep the original data plus at least two backups. One backup can fail without anyone noticing; two rarely do at the same time.
2. Two different types of storage
Store backups on at least two different kinds of storage — for example a local backup appliance and a hosted service — so one hardware problem cannot affect both.
3. One copy off site
Keep at least one copy in a different location. Fire, flooding or theft at the office should not destroy the backups too.
4. Protect against ransomware
Modern ransomware tries to find and encrypt backups. Keep at least one copy that is offline, immutable or protected by separate credentials.
5. Test restores
- Restore a file every month.
- Restore a full system periodically.
- Record how long it took.
6. Back up the right things
Include databases, email, files, system configurations and cloud-hosted data, not just shared folders.
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About the author
Inara Crest Engineering
Engineering team
Written by the Inara Crest Technologies engineering team, who design, install and support software, network, security, power and data centre systems for organisations in Kenya and East Africa.