File Systems

Abstract

Since you are reading a book about volume management for highly available UNIX systems in data centers we would like to assume that you have some basic understanding of what a file system is used for. We will spare both your time and ours describing the basic goals of a file system. But there are some essential differences between the various types of file systems that are very useful to point out. So let us begin with a short overview of the various file system types that have developed over time, and how their strengths increased. Yes, increased, not changed. As a general rule, file systems have indeed gotten a lot better over time without losing any important features relative to older implementations. Different from other aspects of computer technology one can safely say that so far, file system development has been a one-way road towards improvement, not heavily traded-off bloatware development as so many other parts of operating systems. At least if we ignore the nonsequential access methods of some older file systems. But those can be easily emulated on a higher level, and their omission from file system code probably improved performance rather than diminishing it.