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. Fields on each line are separated by tabs
       or spaces. 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.

HISTORY

       The ancestor of this fstab file format appeared in 4.0BSD.

SEE ALSO

       getmntent(3), fs(5), findmnt(8), mount(8), swapon(8)

REPORTING BUGS

       For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

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/>.