Show HN: PostgreSQL backup tool Databasus moved to PG 17 native physical backups

An earlier version of Databasus shipped a backup agent: a binary that ran on the database host to stream WAL and create physical backups locally. That first implementation turned out to be a mistake, and we removed it. Physical backups now run remotely from the Databasus host, as described above.

Why the agent was the wrong approach:

• It was a naive implementation that only copied WAL on top of full backups, which led to a long RTO

• Users had to configure both Databasus and a separate agent, when doing everything remotely from one place is far simpler

• Because the agent lived outside the main system, it was hard to cover every test case

• There is really only one problem an agent solves: reaching a database that is not accessible from outside. For 99% of users that is already handled by running Databasus inside the private network or connecting over SSH, so the agent was reinventing the wheel and making a simple problem far more complicated than it needed to be

• It could not run on managed databases like RDS and Cloud SQL, which forbid host-level installs but already expose the replication protocol, so a remote path was needed anyway

• It also came with a lot of edge cases. Broken connections, managing agent updates and gathering logs from a separate process were all painful, and the fewer moving parts a system has, the more reliable it is in everyday use

So now we use PostgreSQL 17 native backups instead. What that gives you:

• They reuse PostgreSQL's own backup machinery instead of reinventing it, so you get battle-tested internals with thousands of tests and edge cases behind them

• They work with remote databases, including managed services like Amazon RDS and Google Cloud SQL that expose the replication protocol but forbid installing software on the host

• They give near-zero data loss, letting you restore to any second between backups with low RTO / RPO

We made sure existing backups stay safe. If you upgrade from a version that still has agent backups, Databasus won't do it silently: it warns you about the change and lets you either stay on the supported version 3.42.0 or remove the old agent backups yourself before upgrading. The agent-based implementation remains available up to version 3.42.0 and will keep working for a long time, so nothing breaks.

You can read the full reasoning in the architecture decision records:

ADR-0008: PG17-native backups with mandatory WAL summary https://github.com/databasus/databasus/blob/main/adr/0008-wh...

ADR-0009: remote physical backups instead of agents https://github.com/databasus/databasus/blob/main/adr/0009-wh...

By the way, Databasus recently crossed 7,500 GitHub stars and over 1 million Docker Hub pulls. Thank you for such love to the project. It really keeps us going, and a lot of what shipped here came straight from your issues, PRs and feedback. We're just getting started!