Chapter 30. The Linux File System Your GNU/Linux
Chapter 30. The Linux File System Your GNU/Linux system is contained on your hard disk within a file system. In this chapter we will discuss the various aspects of file systems available on GNU/Linux, as well as the possibilities they offer. 1. Comparing a Few File Systems During installation, you can choose different file systems for your partitions, so they will be formatted using different algorithms. Unless you are a specialist, choosing a file system is not obvious. We will take a quick look at a few current file systems, all of which are available with Mandriva Linux. 1.1. Different Usable File Systems 1.1.1. Ext2 The Second Extended File System (its abbreviated form is ext2FS or simply ext2) has been GNU/Linux’s default file system for many years. It replaced the Extended File System (that’s where the Second comes from). ext2 corrects certain problems and limitations of its predecessor. ext2 respects the usual standards for UNIX-type file systems. Since its inception, it was destined to evolve while still offering great robustness and good performance. Caution: It needs to be unmounted to be resized. 1.1.2. Ext3 As its name suggests, the Third Extended File System is ext2’s successor. It is compatible with the latter but enhanced by incorporating journaling. One of the major flaws of traditional file systems like ext2 is their low tolerance to abrupt system breakdowns (power failure or crashing software). Generally speaking, once the system is restarted, these types of events involve a very long examination of the file system’s structure and attempts to correct errors, which sometimes results in an extended corruption. This corruption could cause partial or total loss of saved data. Journaling answers this problem. To simplify, let’s say that what we are doing is storing the actions (such as the saving of a file) before really performing them. We could compare this functionality to that of a boat captain who uses a log book to