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Nginx, Linux sendfile(), and Problem Solving

Engine room, by Maggie Stephens

In “A Tale of Stale Content”, on the Van Patten Media blog, I take a somewhat philosophical look at IT problem solving, told through the story of an intensely frustrating issue with Nginx serving up stale content in virtualised environments. Apparently, the sendfile on; setting in Nginx will cause it to deliver old versions of files you have since updated on disk.

Sometimes a problem comes up that is just weird. It seems completely illogical. But these computery things are supposed to be nothing but logic, right?

When we eventually arrive at the solution, after many hours of hair loss and bad language, we are reminded of the sheer complexity of these systems. Our assumptions about how something at a higher level should behave are entirely dependent on the premise that the lower levels are all doing exactly as expected too.

It’s humbling, in a slightly odd technical sense. We all need to be humbled sometimes.

Read the full post over on the Van Patten Media blog.

Image is “Engine room”, by Maggie Stephens (Pot Noodle) on Flickr. Licensed under CC-BY.