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There's a NoSql db on every host as well, the filesystem, and it works great for documented oriented sites like blogs.

Yeah, but doesn't the default number of open file descriptors limit how scalable such a solution is as a default to rely on?

Only if your number of pages exceeds the limit (assuming that you're serializing access to the files) ;)

I highly doubt that's an issue you'll ever run into on a blog.