Use ext4 file system in CentOS5.x

Generally, CentOS5.x has ext4 kernel modules but is not loaded. Run the following command cd/lib/modules/*/kernel/fs/ext4/. Note that the command above contains wildcards, because the kernel versions of different systems may be different. Then execute the following command ls-lext4.ko if normal, you can see the ext4 module. -Rwxr -- r -- generally, CentOS 5.x has ext4 kernel modules but is not loaded.

Run the following command first
Cd/lib/modules/*/kernel/fs/ext4/
Note that the preceding command contains wildcards because the kernel versions of different systems may be different.
Then execute the following command
Ls-l ext4.ko
Normally, you can see the ext4 module.
-Rwxr -- r -- 1 root 285684 2010-04-03 ext4.ko

Use the following command to load the ext4 module into the kernel
Modprobe ext4
Then confirm
Lsmod | grep ext4
This line of content is displayed.
Ext4 243693 0

Run the following command to install mkfs. ext4:
Yum-y install e4fsprogs
After installation, you can use the mkfs. ext4 command.

Run the following command to enable the system to load the ext4 kernel module the next time it is started.
Echo "modprobe ext4">/etc/rc. sysinit

All operations are completed.

For common users, the biggest difference between ext3 and ext4 is that ext3 takes a lot of time in fsck (the more files, the longer the time ), however, ext4 uses a lot of time in fsck.
During each Linux system startup (including restart), the last fsck time of the hard disk will be checked. by default, if there is no fsck over 180 days, the fsck will be forced, the system will not be accessed until the end. if the ext3 file system is used, it may take several minutes or even hours.