Backup and Disaster Recovery Basics
A deployment security checklist can only give backups one line among many, and that line is usually just ‘have them.’ It doesn’t have room to answer the questions that actually decide whether a backup saves you or just makes you feel safer: how often, tested how, and recovered how fast.
This guide goes deeper on that one line: two terms worth actually understanding — RTO and RPO — a sane way to think about backup frequency, why an untested backup isn’t really a backup, and the real difference between backing up a database and backing up file storage.
RTO and RPO, defined plainly
Recovery Time Objective (RTO) is how long you can be down before it’s unacceptable — the gap between the disaster and being back online. Recovery Point Objective (RPO) is how much data you can afford to lose — the gap between your last good backup and the moment things went wrong.
The two pull against each other. A tight RPO (near-zero data loss) usually needs continuous or frequent backups, which cost more to run and store. A tight RTO (fast recovery) usually needs automation and a rehearsed process, not just a backup file sitting somewhere. Naming both numbers explicitly, even roughly, turns ‘we have backups’ into an actual plan.
How often should you actually back up?
The honest answer is set by your RPO, not by a generic rule. If losing a day of data would be a minor annoyance, nightly backups are fine. If losing even an hour would be a real problem — orders, payments, anything users would notice missing — you need something closer to continuous, which for a database usually means write-ahead log shipping or point-in-time recovery rather than periodic snapshots.
PostgreSQL’s continuous archiving is a good concrete example of the difference: instead of one backup file taken once a day, the write-ahead log is archived continuously, so a restore can replay forward to almost any specific moment rather than only to the last snapshot.
An untested backup is not a backup
A backup that has never been restored is a hypothesis, not a safety net. Corrupted archives, missing permissions, an incomplete export that silently skipped a table — all of these hide perfectly inside a backup that appears to exist and only reveal themselves the moment you actually need the data back.
A restore drill doesn’t need to be elaborate to be worth doing: periodically restoring a backup into a throwaway environment and confirming the data is actually there and the application actually runs against it is enough to catch the failure modes that matter. Do it on a schedule, not just once.
Database backups vs file-storage backups
A database backup and a file-storage backup protect different things and usually need different tools. A database backup needs to capture a consistent point-in-time snapshot of a system that’s changing constantly underneath it — get this wrong and you can restore a database with half a transaction, which is worse than no backup at all.
File storage — uploaded images, documents, generated exports — is comparatively simpler to back up (mostly static blobs), but it’s easy to forget entirely because it doesn’t live in the database you’re already backing up carefully. A disaster recovery plan that only covers the database and quietly assumes file storage is ‘probably fine’ has a real gap in it.
Frequently asked questions
What is RTO in plain terms?
Recovery Time Objective — the maximum acceptable time between something going wrong and the system being back up. It’s a target for how fast, not a description of your current backup schedule; the gap between the two is exactly the gap a disaster recovery plan needs to close.
What is RPO in plain terms?
Recovery Point Objective — the maximum acceptable amount of data you could lose, measured as time since the last good backup. Nightly backups mean an RPO of up to 24 hours; continuous write-ahead log archiving can bring that down to seconds.
How do you test a backup without risking production data?
Restore it into a separate, throwaway environment — not production — and check that the data is actually complete and the application runs against it correctly. This is the restore drill, and it’s the only way to know a backup works before the day you actually need it to.
Are database backups and file-storage backups really different?
Yes. A database backup has to capture a consistent snapshot of constantly-changing, structured data, which usually needs database-specific tooling (like point-in-time recovery) to do safely. File storage is more often static blobs that are simpler to copy, but easy to leave out of a backup plan entirely because it isn’t part of the database.
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Sources: AWS Whitepaper — Disaster Recovery of Workloads on AWS · PostgreSQL Docs — Continuous Archiving and Point-in-Time Recovery — all accessed 4 August 2026.
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