4.4. Mounting an ext4 File System
mount block_device /mount/point
nouser_xattr, and many others that were already used with the ext2 and ext3 file systems, are backward compatible and have the same usage and functionality. Also, with the ext4 file system, several new ext4-specific mount options have been added, for example:
- barrier / nobarrier
- By default, ext4 uses write barriers to ensure file system integrity even when power is lost to a device with write caches enabled. For devices without write caches, or with battery-backed write caches, you disable barriers using the
mount -o nobarrier block_device /mount/point
- This option allows you to specify the number of file system blocks allocated for a single file operation. For RAID5 this number should be equal the RAID chunk size multiplied by the number of disks.
- This option allows you to set priority of I/O operations submitted during a commit operation. The option can have a value from 7 to 0 (0 is the highest priority), and is set to 3 by default, which is slightly higher priority than the default I/O priority.
tune4fsutility. For example, the following command sets the file system on the
/dev/mapper/VolGroup00-LogVol02device to be mounted by default with debugging disabled and user-specified extended attributes and Posix access control lists enabled:
tune4fs -o ^debug,user_xattr,acl /dev/mapper/VolGroup00-LogVol02
tune4fs(8) manual page.
mount -t ext4 block_device /mount/point
multi-block allocation, and exclude features such as
mount(8) manual page.
/etc/fstabfile accordingly. For example:
/dev/mapper/VolGroup00-LogVol02 /test ext4 defaults 0 0