# fstab

## NAME



           fstab - static information about the filesystems
    


## SYNOPSIS



           _/etc/fstab_
    


## DESCRIPTION



           The file **fstab** contains descriptive information about the
           filesystems the system can mount. **fstab** is only read by programs,
           and not written; it is the duty of the system administrator to
           properly create and maintain this file. The order of records in
           **fstab** is important because fsck(8), mount(8), and umount(8)
           sequentially iterate through **fstab** doing their thing.
    
           The file is not read by mount(8) only but often is used by many
           other tools and daemons, and proper functionality may require
           additional steps. For example, on systemd-based systems, it’s
           recommended to use **systemctl daemon-reload** after **fstab**
           modification.
    
           Each filesystem is described on a separate line, with fields
           separated by tabs or spaces. The line is split into fields before
           being parsed. This means that any spaces or tabs within the fields
           must be escaped using \040 or \011, even within quoted strings
           (e.g. LABEL="foo\040bar").
    
           Lines starting with '#' are comments. Blank lines are ignored.
    
           The following is a typical example of an **fstab** entry:
    
               LABEL=t-home2   /home      ext4    defaults,auto_da_alloc      0  2
    
       **The first field (_fs_spec_).**
           This field describes the block special device, remote filesystem
           or filesystem image for loop device to be mounted or swap file or
           swap device to be enabled.
    
           For ordinary mounts, it will hold (a link to) a block special
           device node (as created by mknod(2)) for the device to be mounted,
           like _/dev/cdrom_ or _/dev/sdb7_. For NFS mounts, this field is
           _< host>:<dir>_, e.g., _knuth.aeb.nl:/_. For filesystems with no
           storage, any string can be used, and will show up in df(1) output,
           for example. Typical usage is _proc_ for **procfs** ; _mem_ , _none_ , or _tmpfs_
           for **tmpfs**. Other special filesystems, like **udev** and **sysfs** , are
           typically not listed in **fstab**.
    
           LABEL=<label> or UUID=<uuid> may be given instead of a device
           name. This is the recommended method, as device names are often a
           coincidence of hardware detection order, and can change when other
           disks are added or removed. For example, 'LABEL=Boot' or
           'UUID=3e6be9de-8139-11d1-9106-a43f08d823a6'. (Use a
           filesystem-specific tool like e2label(8), xfs_admin(8), or
           fatlabel(8) to set LABELs on filesystems).
    
           It’s also possible to use **PARTUUID=** and **PARTLABEL=**. These
           partitions identifiers are supported for example for GUID
           Partition Table (GPT).
    
           See mount(8), blkid(8) or lsblk(8) for more details about device
           identifiers.
    
           Note that mount(8) uses UUIDs as strings. The string
           representation of the UUID should be based on lower case
           characters. But when specifying the volume ID of FAT or NTFS file
           systems upper case characters are used (e.g UUID="A40D-85E7" or
           UUID="61DB7756DB7779B3").
    
       **The second field (_fs_file_).**
           This field describes the mount point (target) for the filesystem.
           For swap area, this field should be specified as `none'. If the
           name of the mount point contains spaces or tabs these can be
           escaped as `\040' and '\011' respectively.
    
       **The third field (_fs_vfstype_).**
           This field describes the type of the filesystem. Linux supports
           many filesystem types: ext4, xfs, btrfs, f2fs, vfat, ntfs,
           hfsplus, tmpfs, sysfs, proc, iso9660, udf, squashfs, nfs, cifs,
           and many more. For more details, see mount(8).
    
           An entry _swap_ denotes a file or partition to be used for swapping,
           cf. swapon(8). An entry _none_ is useful for bind or move mounts.
    
           More than one type may be specified in a comma-separated list.
    
           mount(8) and umount(8) support filesystem _subtypes_. The subtype is
           defined by '.subtype' suffix. For example 'fuse.sshfs'. It’s
           recommended to use subtype notation rather than add any prefix to
           the first fstab field (for example 'sshfs#example.com' is
           deprecated).
    
       **The fourth field (_fs_mntops_).**
           This field describes the mount options associated with the
           filesystem.
    
           It is formatted as a comma-separated list of options and is
           optional for mount(8) or swapon(8). The usual convention is to use
           at least "defaults" keyword there.
    
           It usually contains the type of mount (**ro** or **rw** , the default is
           **rw**), plus any additional options appropriate to the filesystem
           type (including performance-tuning options). For details, see
           mount(8) or swapon(8).
    
           Basic filesystem-independent options are:
    
           **defaults**
               use default options. The default depends on the kernel and the
               filesystem. mount(8) does not have any hardcoded set of
               default options. The kernel default is usually rw, suid, dev,
               exec, auto, nouser, and async.
    
           **noauto**
               do not mount when **mount -a** is given (e.g., at boot time)
    
           **user**
               allow a user to mount
    
           **owner**
               allow device owner to mount
    
           **comment**
               or **x- <name> **for use by fstab-maintaining programs
    
           **nofail**
               do not report errors for this device if it does not exist.
    
       **The fifth field (_fs_freq_).**
           This field is used by **dump**(8) to determine which filesystems need
           to be dumped. Defaults to zero (don’t dump) if not present.
    
       **The sixth field (_fs_passno_).**
           This field is used by fsck(8) to determine the order in which
           filesystem checks are done at boot time. The root filesystem
           should be specified with a _fs_passno_ of 1. Other filesystems
           should have a _fs_passno_ of 2. Filesystems within a drive will be
           checked sequentially, but filesystems on different drives will be
           checked at the same time to utilize parallelism available in the
           hardware. Defaults to zero (don’t check the filesystem) if not
           present.
    


## FILES



           _/etc/fstab_ , _< fstab.h>_
    


## NOTES



           The proper way to read records from **fstab** is to use the routines
           getmntent(3) or **libmount**.
    
           The keyword **ignore** as a filesystem type (3rd field) is no longer
           supported by the pure libmount based mount utility (since
           util-linux v2.22).
    
           This document describes handling of **fstab** by **util-linux** and
           **libmount**. For **systemd** , read **systemd** documentation. There are
           slight differences.
    


## AVAILABILITY



           **fstab** is part of the util-linux package which can be downloaded
           from Linux Kernel Archive
           <https://www.kernel.org/pub/linux/utils/util-linux/>. This page is
           part of the _util-linux_ (a random collection of Linux utilities)
           project. Information about the project can be found at 
           ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have a
           bug report for this manual page, send it to
           util-linux@vger.kernel.org. This page was obtained from the
           project's upstream Git repository
           ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
           2025-08-11. (At that time, the date of the most recent commit that
           was found in the repository was 2025-08-05.) If you discover any
           rendering problems in this HTML version of the page, or you
           believe there is a better or more up-to-date source for the page,
           or you have corrections or improvements to the information in this
           COLOPHON (which is _not_ part of the original manual page), send a
           mail to man-pages@man7.org
    
    util-linux 2.42-start-521-ec46  2025-08-09                       _FSTAB_(5)
    


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