Datasheet

“main” (Installation and Administration) — 2004/6/25 — 13:29 — page 385 — #411
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18
File Systems in Linux
18.2.3 Converting an Ext2 File System into Ext3
Converting from Ext2 to Ext3 involves two separate steps:
Creating the Journal Log in as root and run tune2fs -j. This creates
an Ext3 journal with the default parameters. To decide yourself how
large the journal should be and on which device it should reside,
run tune2fs -J instead together with the desired journal options
size= and device=. More information about the tune2fs program
is available in its manual page (man 8 tune2fs).
Specifying the File System Type in /etc/fstab
To ensure that the Ext3 file system is recognized as such, edit the
file /etc/fstab, changing the file system type specified for the
corresponding partition from ext2 to ext3. The change takes effect
after the next reboot.
Using ext3 for the Root Directory
To boot a root file system set up as an ext3 partition, include the
modules ext3 and jbd in the initrd. To do so, edit the file
/etc/sysconfig/kernel to include the two modules under
INITRD_MODULES then execute the command mk_initrd.
18.2.4 ReiserFS
Officially one of the key features of the 2.4 kernel release, ReiserFS has been
available as a kernel patch for 2.2.x SUSE kernels since SUSE LINUX ver-
sion 6.4. ReiserFS was designed by Hans Reiser and the Namesys devel-
opment team. ReiserFS has proven to be a powerful alternative to the old
Ext2. Its key assets are better disk space utilization, better disk access per-
formance, and faster crash recovery. However, there is a minor drawback:
ReiserFS pays great care to metadata but not to the data itself. Future gen-
erations of ReiserFS will include data journaling (both metadata and actual
data are written to the journal) as well as ordered writes.
ReiserFS’s strengths, in more detail, are:
Better Disk Space Utilization In ReiserFS, all data is organized in a struc-
ture called B
*
-balanced tree. The tree structure contributes to better
disk space utilization as small files can be stored directly in the B
*
tree leaf nodes instead of being stored elsewhere and just maintain-
ing a pointer to the actual disk location. In addition to that, storage is
385SUSE LINUX Enterprise Server