/dev/null is an ACID compliant database

Original Article ↗ Hacker News Discussion ↗

Humorous framing of /dev/null as a database

  • Most comments lean into the joke: /dev/null as the perfect, infinitely scalable, ACID- and CAP-compliant “database” with zero bugs, no support issues, and massive cost savings once all data is piped into it.
  • People riff on real-sounding productization: “Null as a Service” (NaaS), devnull-as-a-service.com, enterprise policies with /dev/null0 and /dev/null1, audits, and DR runbooks.
  • Support and analytics jokes: routing tickets and logs to /dev/null “solves” reliability and throughput problems.

ACID, CAP, and pedantic pushback

  • Several point out that /dev/null is not actually a database, more a storage sink.
  • Durability is debated: some argue it trivially satisfies durability because nothing is stored; others insist durability refers to preserving user data, which clearly fails here.
  • Similar nitpicks about “state transitions” when there is effectively only one state, and that the joke relies on colloquial, not formal, definitions of ACID.

Real-world behavior and failure modes

  • /dev/null can fail in practice: missing /dev, running out of file descriptors or memory, or /dev/null being replaced by a regular file or a different device (allowing data capture or system instability).
  • Disaster recovery is tongue-in-cheek: you can recreate it with mknod and chmod, and “all the same data will be there” because it’s always empty.

Performance, scalability, and “web scale”

  • Benchmarks show tens of GB/s when writing /dev/zero to /dev/null; others test pipes (yes | pv) and observe pipe or tool overheads.
  • Many jokes about horizontal sharding, global sharding “across the universe,” Kubernetes deployments, and “Heisen-throughput” that scales as high as you can measure.

Related satire and analogies

  • References to S4 (Super Simple Storage Service), write-only memory, “mangodb,” nocode, supersimplestorageservice.com, and pipe-logic/circuit analogies.
  • A few criticize the joke as weak or sloppy; others defend it as classic nerd humor and a “trivial solution” that usefully highlights how ACID/CAP definitions can be vacuous.

Security / tampering angle

  • One concern: a privileged user can replace /dev/null with a normal file or different device, allowing interception of “discarded” data.