[kbenson]

The benefit of bringing something in process is as always more control, and usually at the expense of having to make decisions with less data about the rest of the system than an OS level service would have.

Sometimes you need very explicit control over when things are read from cache and when they aren't. This can be hard with network file systems. Especially when you have two different use cases on the same filesystem, which isn't that odd, even within a single application.