FSTAB(5) - man - phpman

FSTAB(5)                                    File formats                                    FSTAB(5)



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.

       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 partition 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 partitions, 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. It contains at least the type of mount
       (ro or 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: 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).

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/karelzak/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/>.



util-linux 2.37.2                            2021-06-02                                     FSTAB(5)