{"id":"macos-fsync-not-durable-without-fullfsync","text":"On macOS (the development platform), `os.fsync()` may not flush the disk's hardware write cache; true power-loss durability requires `fcntl(fd, F_FULLFSYNC)` which is never used in the codebase.","truth_value":"IN","source":"entries/2026/05/29/topic-fsync-ordering-guarantees.md","source_url":"","source_hash":"","justifications":[],"dependents":["wal-durability-effective-on-standards-compliant-fsync"],"metadata":{},"created_at":"","updated_at":"","reviewed_at":"","verified_at":"","retracted_at":"","explanation":{"steps":[{"node":"macos-fsync-not-durable-without-fullfsync","truth_value":"IN","reason":"premise"}]}}