Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 08-05-2008 Installation Manual page 489

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directly in the B
taining a pointer to the actual disk location. In addition to that, storage is not allo-
cated in chunks of 1 or 4 KB, but in portions of the exact size needed. Another
benefit lies in the dynamic allocation of inodes. This keeps the file system more
flexible than traditional file systems, like Ext2, where the inode density must be
specified at file system creation time.
Better Disk Access Performance
For small files, file data and "stat_data" (inode) information are often stored next
to each other. They can be read with a single disk I/O operation, meaning that only
one access to disk is required to retrieve all the information needed.
Fast Crash Recovery
Using a journal to keep track of recent metadata changes makes a file system check
a matter of seconds, even for huge file systems.
Reliability through Data Journaling
ReiserFS also supports data journaling and ordered data modes similar to the con-
cepts outlined in the Ext3 section,
mode is data=ordered, which ensures both data and metadata integrity, but
uses journaling only for metadata.
25.2.2 Ext2
The origins of Ext2 go back to the early days of Linux history. Its predecessor, the
Extended File System, was implemented in April 1992 and integrated 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
pending files or data blocks are written to a designated directory (called lost
tree leaf nodes instead of being stored elsewhere and just main-
Section 25.2.3, "Ext3" (page 472). The default
File Systems in Linux 471