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3.2. Mounting an XFS File System

An XFS file system can be mounted with no extra options, for example:
# mount /dev/device /mount/point
The default for Red Hat Enterprise Linux 7 is inode64.


Unlike mke2fs, mkfs.xfs does not utilize a configuration file; they are all specified on the command line.

Write Barriers

By default, XFS 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, disable the barriers by using the nobarrier option:
# mount -o nobarrier /dev/device /mount/point
For more information about write barriers, see Chapter 22, Write Barriers.

Direct Access Technology Preview

Since Red Hat Enterprise Linux 7.3, Direct Access (DAX) is available as a Technology Preview on the ext4 and XFS file systems. It is a means for an application to directly map persistent memory into its address space. To use DAX, a system must have some form of persistent memory available, usually in the form of one or more Non-Volatile Dual Inline Memory Modules (NVDIMMs), and a file system that supports DAX must be created on the NVDIMM(s). Also, the file system must be mounted with the dax mount option. Then, an mmap of a file on the dax-mounted file system results in a direct mapping of storage into the application's address space.