Whys of backup

• For: anyone whose work lives on a computer and who has never set up a backup.
• Before you start: nothing. This is the argument; the next chapter is the procedure.
• Reading time: about 8 minutes.
• You end with: the reasons to back up, to keep the copy offline and off the cloud, and to start today.

TL;DR

Get a working backup running today. Someday a life could depend on it. Borg is the best backup tool so far. Start simple. Iterate later. Don’t put your backups online. Bring your data into a single folder, get a couple of USB sticks, and proceed to the next chapter.

Why backup?

Setting up a reliable backup system is the first thing every serious knowledge worker should do.

Data loss is inevitable

There are two kinds of people, as an old saying goes: those who have lost important data and those who will. Drives fail. Devices get stolen. Mistakes happen. Malware corrupts or locks what you have. The question is not whether you will face data loss, but whether you will be prepared for it.

Recovery is a pain

Recovery without a backup is painful and time-consuming. The asymmetry between the effort of setting up and running a good backup system and the agony of recovering lost data without one is vast. The effort to set up a backup system fades in comparison to the peace that comes from knowing that it’s going to be very hard for you to lose data. Moreover, to keep a backup system going costs almost nothing. The hard part is the one-time work to set it up. This section is meant to reduce the effort, and once you’ve understood the principles, setting up a quality backup could take you less than an hour.

Someone’s life may depend on it

Data is not a luxury. It shapes how you work, how you remember, how you prove who you are and what you have done. For most people, the loss of important data is a serious inconvenience. For some it can be catastrophic: a doctor whose patient records vanish, a journalist whose source files are wiped, a small business owner whose client database disappears overnight. And sometimes, the right file is the difference between life and death: a medical history in an emergency room, the evidence that clears someone, the records that locate a missing person.

It’s a way to honour time

Even if the stakes may not be as high or dramatic, it’s prudent to honour your time. Data represents time, our most finite and non-renewable resource. Every file created, every note written, every photograph you’ve taken is time spent. To be careless with it is to dishonour your time. A backup plan is, among other things, an act of respect for your own labour and time.

Why offline?

Offline backups are the only real defence against malware. Anything your running system can write to, a virus can destroy. Ransomware encrypts every mounted volume it can find. Data loss doesn’t have to come from external attacks. An accidental sync request replicates your deletion faithfully and instantly. But an offline backup, a medium that spends most of its life physically unplugged, is the only defence in such cases.

Why not cloud services?

Offline backups are the responsible thing to do. Don’t upload your data to Google Drive or OneDrive or some other storage service. That’s a bad idea even if it’s encrypted. Take responsibility for what’s yours. Don’t be a wuss.

Who says it’s encrypted?

Most consumer cloud is not end-to-end encrypted at all. “Encrypted at rest” means the provider keeps a key and can read your files whenever it chooses. There is nothing for an attacker to break, because the provider can already decrypt, and so can anyone who breaches them, buys them, or compels them. Even the services that are genuinely end-to-end write and ship the software that does the encrypting. A single update can lift your key, or your files, before they are ever encrypted, and you cannot audit every release. Unless it’s a fully open-source app, not just source-available, don’t trust it.

Your custodian is a moving target

The company can be breached, sold, merged, subpoenaed, served a foreign warrant, or simply shut down. It can change its terms or close your account on a morning you had no reason to expect. Furthermore, providers consolidate, so the entity holding your data next year may not be the one you chose this year. Legal demands on them rise rather than fall. Their incentive to mine what you store, to train models on it, or to sell access to it climbs every quarter.

The stored copy only gets easier to open

“Well what if I encrypt and use cloud only for syncing and a safety net?” Still no. There is the long game you have to consider. An attacker does not have to break your encryption now. He copies your encrypted files out of the cloud today and simply waits. Computers keep getting stronger, and the quantum kind is expected to break the public-key encryption in wide use today. When that day arrives, the attacker unlocks the copy he took years before. Most of the ciphers and hashes in wide use before roughly 2000 have since been broken, weakened, or retired: DES, RC4, MD5 and SHA-1 among them. As recently as July 2026, Anthropic reported attacks that used Claude Mythos Preview to significantly weaken HAWK, a post-quantum digital signature scheme, and to identify a new way to attack round-reduced AES. Now most real-world cryptographic loss came from key sizes ageing out, implementation bugs, protocol design, and deliberate sabotage, not from mathematicians cracking the core algorithm; yet handing over your data means you’re still subject to this attack.

Offline removes the remote attack surface

An offline drive has no remote attack surface, no account to phish, no client to backdoor, no provider to compel, no stored blob to harvest. Your threat model shrinks to the physical: fire, flood, theft, and you deal with physical failures the simple way: keep more than one copy in more than one place. Physical risks do not scale the way network risks do. Breaching one server affects a million people at once, but how does one burgle a million drawers? The chances of an attacker reaching the drive in your home, the drive at your friend’s home, and the drive buried safely in your ancestral home all on the same afternoon are slim. Offline backups give you a boundary you can see, inspect, and defend.

Tradeoffs and solution

Offline drives protect you from data loss only as long as you can reach them. If a fire, a flood, or a tyrannical government means fleeing with what’s in your hands or with nothing at all, the offline drives are useless unless you kept some in different locations or jurisdictions. The drawback here, though, is that these drives are not synced to your latest state. And when the offline drawer of drives isn’t enough, and you want a copy that lives somewhere remote, the solution is still hardware you own: a home server hosted on a machine you control in a different city or country, rather than a company’s cloud. Walk out with the passphrase in your head and the data is still yours.

Why Borg?

Borg is not the only backup-program, but it is a very good one, most likely the best one available today. Don’t take my word for it; do your research, but here are some facts.

Nobody bases a product on a backup engine they do not trust. BorgBase, a hosting service specialised for BorgBackup, offers append-only repositories and two-factor authentication, and it funds development of the surrounding tooling. Hetzner, a German cloud and hosting provider known for affordable, high-performance servers, added native Borg support to its Storage Box product, with an extended SSH service, official documentation, append-only mode, and per-version remote-path pinning. Rsync.net, one of the longest-standing offsite-storage providers, supports Borg natively as well. On the desktop, Pika Backup, a GNOME application, is powered by BorgBackup, and Vorta provides a Qt front-end over the same Borg backend, while Borgmatic wraps it for scheduling and retention policy. A whole ecosystem of CLIs, Docker servers, and web UIs has grown around the engine.

Borg’s headline accomplishment is reach. The main repository carries roughly 14k stars (at the time of this writing). Borg ships as a packaged tool in the Debian, Fedora, and Arch repositories among others, meaning distribution maintainers vetted and adopted it independently rather than leaving it to users. That’s saying a lot. The Open Source Everything list names it as the backup tool. That’s evidence that experts use it rather than just star it.

On reliability it has earned trust the hard way. Borg deliberately reuses the system SSH client and links only OpenSSL’s libcrypto rather than implementing its own network crypto protocol, and it publishes an explicit threat model spelling out that an attacker cannot modify, rename, remove, or add an archive without the client detecting it. It has run in production for about a decade, descending from Attic, which was accepted into Debian in August 2013 before being forked as Borg in 2015, and it is still actively maintained: lead developer Thomas Waldmann and the project run on community funding through GitHub Sponsors and Open Collective. Across that decade it has had one notable cryptographic flaw, CVE-2023-36811, an archive-forgery issue disclosed and fixed in version 1.2.5 with a documented upgrade procedure, which is the responsible-handling record that matters more than any clean-sheet claim.

Borg uses a technique called deduplication, which means, after the first backup, it only stores the changes of the files being backed up, making it suitable for daily, hourly, and even minute-by-minute backups. It supports compression and authenticated encryption, which makes it suitable for storing backups in untrusted locations. To learn more, read the official docs, and verify for yourself if it fits your needs.

Why today?

The perfect backup system is worth striving for, but it’s unlikely you’re going to build it all today (it’s possible though if you follow through with this series of chapters). And the perfect system will always be worse than a working one that’s running today. A single working encrypted backup on an external drive and a passphrase written on paper is much better than the perfect system you get to eventually. Moreover, the perfect backup system is a moving target; the bad guys will never stop trying to find ways to undermine your privacy and sovereignty. And significant improvements in security and resilience do not need the perfect setup; they need a setup that actually runs today. So start simple. Iterate later.

Now the ‘Levelling up’ pages that come later in this series help you set up a darn good system quickly, but they assume you have your data arranged, you’re using Linux, and you understand the principles of a quality backup-system. But if you don’t have a local working backup, it’s important to first learn the basics, the bare essentials, before you move on to a complex system. Knowing the basics hopefully gets you out of trouble when the fancy setup fails.

To proceed in the recommended order, bring your data into a single folder, and use Borg to back it up onto a USB. The next chapter helps you do just that. If you’re not convinced of Borg, use dummy data for now. Get a feel for how easy the backup process with Borg really is; a few simple commands in your terminal and you have an encrypted, compressed backup. Then do your research; and when you’re convinced that Borg is the best, you can repeat the steps with your actual data.