[oogali]

Writing to a pipe is different from writing to a local file, only because you have to be aware of what's going on behind the scenes.

If the other side of the pipe closes (e.g. syslog-ng), your process will hang once the I/O buffer fills up, which is generally 4KB.

You especially need to keep this in mind, when syslog-ng restarts (pipe closed, pipe reopened). You'll probably glance quickly to see that syslog-ng is running, and the pipe is present, but wonder why nginx is not serving traffic.

Or worse, be fooled into thinking nginx is fine because it was serving traffic up until it served 50 requests (or however many reqs it takes to generate 4,000 bytes of access logs), then stopped.