Tech article
Your Filesystem Is Lying to You: Why fsync() Doesn't Guarantee Durability
Community description: Why fsync() doesn't actually guarantee data durability — the hidden kernel and storage gaps every developer should know.
Dev.to | Sep 14, 2026 | Syed Anzar
Automated excerpt
Later, when PostgreSQL executed fsync(), the kernel saw the error flag, returned EIO (Error), and cleared the error flag. When PostgreSQL retried fsync() on the next check, the kernel saw no dirty pages and no error flag, returning 0 (Success)! Audit storage hardware for Power Loss Protection (PLP) before relying on hardware cache flushes.
Selected automatically from source text; not independently written or fact-checked. Read the original for full context.