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FSTAB(5)                  FreeBSD File Formats Manual                 FSTAB(5)

     fstab -- static information about the filesystems

     #include <fstab.h>

     The file fstab contains descriptive information about the various file
     systems.  fstab is only read by programs, and not written; it is the duty
     of the system administrator to properly create and maintain this file.
     Each filesystem is described on a separate line; fields on each line are
     separated by tabs or spaces.  The order of records in fstab is important
     because fsck(8), mount(8), and umount(8) sequentially iterate through
     fstab doing their thing.

     The first field, (fs_spec), describes the block special device or remote
     filesystem to be mounted.  For filesystems of type ufs, the special file
     name is the block special file name, and not the character special file
     name.  If a program needs the character special file name, the program
     must create it by appending a ``r'' after the last ``/'' in the special
     file name.

     The second field, (fs_file), describes the mount point for the filesys-
     tem.  For swap partitions, this field should be specified as ``none''.

     The third field, (fs_vfstype), describes the type of the filesystem.  The
     system can support various filesystem types.  Only the root, /usr, and
     /tmp filesystems need be statically compiled into the kernel; everything
     else will be automatically loaded at mount time.  (Exception: the UFS
     family - FFS, MFS, and LFS cannot currently be demand-loaded.)  Some peo-
     ple still prefer to statically compile other filesystems as well.

           ufs     a local UNIX filesystem

           mfs     a local memory-based UNIX filesystem

           nfs     a Sun Microsystems compatible ``Network File System''

           swap    a disk partition to be used for swapping

           msdos   a DOS compatible filesystem

           cd9660  a CD-ROM filesystem (as per ISO 9660)

           procfs  a file system for accessing process data

     The fourth field, (fs_mntops), 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 (see fs_type below) plus
     any additional options appropriate to the filesystem type.  See the
     options flag (-o) in the mount(8) page and the filesystem specific page,
     such as mount_nfs(8), for additional options that may be specified.

     If the options ``userquota'' and/or ``groupquota'' are specified, the
     filesystem is automatically processed by the quotacheck(8) command, and
     user and/or group disk quotas are enabled with quotaon(8).  By default,
     filesystem quotas are maintained in files named quota.user and which are located at the root of the associated filesystem.
     These defaults may be overridden by putting an equal sign and an alterna-
     tive absolute pathname following the quota option.  Thus, if the user
     quota file for /tmp is stored in /var/quotas/tmp.user, this location can
     be specified as:


     If the option ``noauto'' is specified, the filesystem will not be auto-
     matically mounted at system startup.  This is recommended for all remote
     filesystems other than NFS, since only NFS mounts are delayed until after
     network initialization by the rc startup scripts.

     The type of the mount is extracted from the fs_mntops field and stored
     separately in the fs_type field (it is not deleted from the fs_mntops
     field).  If fs_type is ``rw'' or ``ro'' then the filesystem whose name is
     given in the fs_file field is normally mounted read-write or read-only on
     the specified special file.  If fs_type is ``sw'' then the special file
     is made available as a piece of swap space by the swapon(8) command at
     the end of the system reboot procedure.  The fields other than fs_spec
     and fs_type are unused.  If fs_type is specified as ``xx'' the entry is
     ignored.  This is useful to show disk partitions which are currently

     The fifth field, (fs_freq), is used for these filesystems by the dump(8)
     command to determine which filesystems need to be dumped.  If the fifth
     field is not present, a value of zero is returned and dump will assume
     that the filesystem does not need to be dumped.

     The sixth field, (fs_passno), is used by the fsck(8) program to determine
     the order in which filesystem checks are done at reboot time.  The root
     filesystem should be specified with a fs_passno of 1, and other filesys-
     tems 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.  If
     the sixth field is not present or is zero, a value of zero is returned
     and fsck(8) will assume that the filesystem does not need to be checked.

     #define FSTAB_RW        "rw"    /* read/write device */
     #define FSTAB_RQ        "rq"    /* read/write with quotas */
     #define FSTAB_RO        "ro"    /* read-only device */
     #define FSTAB_SW        "sw"    /* swap device */
     #define FSTAB_XX        "xx"    /* ignore totally */

     struct fstab {
             char    *fs_spec;       /* block special device name */
             char    *fs_file;       /* filesystem path prefix */
             char    *fs_vfstype;    /* File system type, ufs, nfs */
             char    *fs_mntops;     /* Mount options ala -o */
             char    *fs_type;       /* FSTAB_* from fs_mntops */
             int     fs_freq;        /* dump frequency, in days */
             int     fs_passno;      /* pass number on parallel fsck */

     The proper way to read records from fstab is to use the routines
     getfsent(3), getfsspec(3), getfstype(3), and getfsfile(3).

     /etc/fstab  The file fstab resides in /etc.

     getfsent(3), getvfsbyname(3), dump(8), fsck(8), mount(8), quotacheck(8),
     quotaon(8), swapon(8), umount(8)

     The fstab file format appeared in 4.0BSD.

FreeBSD 4.10                     June 5, 1993                     FreeBSD 4.10


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