Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 383 — #409
i
i
i
i
i
i
i
i
18
File Systems in Linux
Note
Setting up File Systems
Unless stated otherwise in this chapter, all the steps required to
set up or to change partitions and file systems can be performed
using the YaST module.
Note
18.2.1 Ext2
The origins of Ext2 go back to the early days of Linux history. Its predeces-
sor, the Extended File System, was implemented in April 1992 and inte-
grated in Linux 0.96c. The Extended File System underwent a number of
modifications and, as Ext2, became the most popular Linux file system for
years. With the creation of journaling file systems and their astonishingly
short recovery times, Ext2 became less important.
A brief summary of Ext2’s strengths might help understand why it was —
and in some areas still is — the favorite Linux file system of many Linux
users.
Solidity Being quite an “old-timer,” Ext2 underwent many improvements
and was heavily tested. This may be the reason why people often
refer to it as rock-solid. After a system outage when the file system
could not be cleanly unmounted, e2fsck starts to analyze the file
system data. Metadata is brought into a consistent state and pend-
ing files or data blocks are written to a designated directory (called
lost+found). In contrast to journaling file systems, e2fsck analyzes
the entire file system and not just the recently modified bits of meta-
data. This takes significantly longer than checking the log data of a
journaling file system. Depending on file system size, this procedure
can take half an hour or more. Therefore, it is not desirable to choose
Ext2 for any server that needs high availability. Yet, as Ext2 does not
maintain a journal and uses significantly less memory, it is sometimes
faster than other file systems.
Easy Upgradability The code for Ext2 is the strong foundation on which
Ext3 could become a highly-acclaimed next-generation file system. Its
reliability and solidity were elegantly combined with the advantages
of a journaling file system.
383SUSE LINUX Enterprise Server