What is the 3-2-1 backup rule?
The 3-2-1 backup rule is a best practice for protecting your data against loss. It states that you should have:
- 3 copies of your data
- In 2 different formats
- With 1 copy offsite
This rule helps ensure that even if some of your backups fail or get destroyed (e.g. by ransomware or natural disaster), you still have other copies to restore from.
Why follow the 3-2-1 backup rule?
There are a few key reasons why the 3-2-1 backup rule is recommended:
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Protects against hardware failure – Hard drives can fail at any time. By keeping copies in two different formats, if one drive fails you still have another backup copy.
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Safeguards against software corruption – Ransomware or bugs could corrupt data. Different formats (e.g. physical media vs cloud storage) help isolate copies from corruption.
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Recovers from catastrophic events – Whether it’s fire, flooding, or theft, an offsite copy helps you recover if disaster strikes your local backups.
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Allows for restoring older versions – Having multiple backups makes it easier to restore from an earlier point in time.
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Gives peace of mind – Knowing you have reliable backups in place lets you sleep better at night!
Breaking down the 3-2-1 backup components
Let’s explore each element of the 3-2-1 backup rule in more detail:
3 Copies of Data
This means having at least three total copies of your important files. Here’s a typical setup:
- Original data on your local computer or network storage. This is one copy.
- Local backup to an external hard drive or network attached storage (NAS). This is the second copy.
- Offsite backup to the cloud or remote location. This is the third copy.
Having multiple redundant copies ensures that if one copy becomes unavailable, you can recover from another.
2 Different Storage Formats
Keeping copies in two different storage formats helps protect against technical issues. Examples include:
- Local HDD and cloud storage
- NAS and external HDD
- Cloud storage from two providers
If one has problems, the other storage format should have unaffected copies of your data. Mixing storage media reduces correlated failures.
1 Offsite Copy
Storing at least one backup offsite (at a remote facility or in the cloud) provides protection against local disasters like fires, floods, and theft. Common offsite backups include:
- Cloud storage – Services like Amazon S3, Backblaze B2
- Remote servers – Storing backups at a colocation facility
- External HDDs – Storing removable drives securely offsite
Offsite backups ensure you can recover data even after severe damage to systems onsite.
Examples of 3-2-1 backup implementations
Here are some examples of how the 3-2-1 backup policy can be implemented:
Small Business
- Original: Server with important files
- Local: External HDDs plugged into the server
- Offsite: Cloud backup to Backblaze
This simple setup has the original data on the server, and two backup copies – one on external HDDs onsite, one in the cloud offsite.
Larger Business
- Original: Primary NAS with database, files
- Local: Daily backups to secondary NAS
- Offsite: Weekly cloud backups to S3 glacier
Here the original data is on a NAS, with local backups to a secondary NAS, and offsite backups to Amazon S3 glacier for long-term archiving.
Home User
- Original: Laptop internal SSD
- Local: External HDD stored at home
- Offsite: Backblaze cloud backup
For home users, original data may be on a laptop or desktop computer, with external HDDs as local backups and cloud storage for offsite.
Best practices for 3-2-1 backups
To get the most out of a 3-2-1 backup solution, here are some key tips to follow:
- Perform backups daily for local copies, at least weekly for offsite copies.
- Validate backup integrity through test restores.
- Encrypt backup data to protect against unauthorized access.
- Use storage media designed for long-term storage for archive copies.
- Store offsite backups sufficiently far to avoid same disaster.
- Consider using different cloud providers for redundancy.
- Automate backups so they run on a schedule.
- Manage backup costs by archiving older data to cheaper storage tiers.
Conclusion
The 3-2-1 backup rule provides a simple but effective data protection strategy. By maintaining at least 3 copies, in 2 formats, with 1 offsite, you can ensure you have reliable backups to protect against data loss scenarios. Following best practices for performing and testing backups makes the 3-2-1 approach even more robust.
Having well-designed backups in place gives you confidence that you can recover from incidents like hardware failures, ransomware, natural disasters, or human errors. And being prepared with tested backups helps you minimize downtime and lost data if disaster ever strikes.
