> The fine print: Due to the architecture of file system access in contemporary kernels (esp. file system caches), it's next to impossible for a user-space appl

> The fine print: Due to the architecture of file system access in contemporary kernels (esp. file system caches), it's next to impossible for a user-space application to actually guarantee that writes are durable (i.e. synced to disk at a defined point in time), but most RDBMS manage well enough in practice. While this doesn't relate to a specific file, you can always look at the size of Dirty and Writeback in /proc/meminfo. They correspond to the amount of dirty file page caches that have yet to be synced.