"The file system is one of the most important parts of an operating system. The file system stores and manages user data on disk drives, and ensures that what's read from storage is identical to what was originally written. In addition to storing user data in files, the file system also creates and manages information about files and about itself. Besides guaranteeing the integrity of all that data, file systems are also expected to be extremely reliable and have very good performance.
"For the past several years, Ext2 has been the de facto file system for most Linux machines. It's robust, reliable, and suitable for most deployments. However, as Linux displaces Unix and other operating systems in more and more large server and computing environments, Ext2 is being pushed to its limits. In fact, many now common requirements--large hard-disk partitions, quick recovery from crashes, high-performance I/O, and the need to store thousands and thousands of files representing terabytes of data--exceed the abilities of Ext2.
"Fortunately, a number of other Linux file systems take up where Ext2 leaves off. Indeed, Linux now offers four alternatives to Ext2: Ext3, ReiserFS, XFS, and JFS. In addition to meeting some or all of the requirements listed above, each of these alternative file systems also supports journaling, a feature certainly demanded by enterprises, but beneficial to anyone running Linux. A journaling file system can simplify restarts, reduce fragmentation, and accelerate I/O. Better yet, journaling file systems make fscks a thing of the past..."
