Raw Or Cooked?
Another hotly contested issue is whether the database should reside in raw, unmounted disk or in cooked operating system files. Once again, the official Informix position is that we dont really care what the underlying disk technology is, as long as we can access it, we will use it and use it as well as it can be used. Operating system vendors say that their performance matches raw disk, but actual end user benchmarking reveals that there is a potential 15-25% performance penalty overall using cooked (block) devices versus using raw (character) devices. This is caused by the overhead of copying the data a second time to/from the Informix buffers and the operating system buffer cache before/after writing/reading disk. This extra step has a fixed cost that varies based on hardware and no high-speed file system or operating system can improve it. In addition, there is another potential 5-30% performance penalty if Informix chunks are created from file system files instead of device files
