4.3. Creating an ext4 File System

After installation, it is sometimes necessary to create a new ext4 file system. For example, if you add a new disk drive to the system, you may want to partition the drive and use the ext4 file system.

The default options are optimal for most usage scenarios but if you need to set your ext4 file system in a specific way, see manual pages for the mke4fs and mkfs.ext4 commands for available options. Also, you may want to examine and modify the configuration file of mke4fs, /etc/mke4fs.conf, if you plan to create ext4 file systems more often.

The steps for creating an ext4 file system are as follows:

A valid block device could be one of two types of entries:

For striped block devices (for example RAID5 arrays), the stripe geometry can be specified at the time of file system creation. Using proper stripe geometry greatly enhances performance of an ext4 file system.

When creating file systems on lvm or md volumes, mkfs.ext4 chooses an optimal geometry. This may also be true on some hardware RAIDs which export geometry information to the operating system.

To specify stripe geometry, use the -E option of mkfs.ext4 (that is, extended file system options) with the following sub-options:

For both sub-options, value must be specified in file system block units. For example, to create a file system with a 64k stride (that is, 16 x 4096) on a 4k-block file system, use the following command:

~]# mkfs.ext4 -E stride=16,stripe-width=64 block_device

For more information about creating file systems, refer to man mkfs.ext4.