Saying that you are implementing a NoSQL approach really means that you are removing an abstraction layer from your data model. The only way I can think of to describe this is to say that you are instead depending on services provided by the operating system. I agree completely that loading a server log into a database table is not the best way to access it. Notice then that you are going to be using disk file IO.

Of course such services, being lower level, can easily be faster. They will also be more complex and require more time and skill to implement and maintain. They will also be less robust in terms of failures and error reporting. In my world of business software development, such systems are implemented by engineers. When I need such functionality, I look for a packaged product, and I personally would not touch such a system, professionally, with a ten foot pole.