4.4BSD/usr/share/man/cat5/fstab.0

FSTAB(5)                    BSD Programmer's Manual                   FSTAB(5)

NNAAMMEE
     ffssttaabb - static information about the filesystems

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<ffssttaabb..hh>>

DDEESSCCRRIIPPTTIIOONN
     The file ffssttaabb contains descriptive information about the various file
     systems.  ffssttaabb 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 ffssttaabb is important
     because fsck(8),  mount(8),  and umount(8) sequentially iterate through
     ffssttaabb doing their thing.

     The first field, (_f_s___s_p_e_c), describes the block special device or remote
     filesystem to be mounted.  For filesystems of type _u_f_s, 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, (_f_s___f_i_l_e), describes the mount point for the filesys-
     tem.  For swap partitions, this field should be specified as ``none''.

     The third field, (_f_s___v_f_s_t_y_p_e), describes the type of the filesystem.  The
     system currently supports four types of filesystems:

           _u_f_s     a local UNIX filesystem

           _m_f_s     a local memory-based UNIX filesystem

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

           _s_w_a_p    a disk partition to be used for swapping

     The fourth field, (_f_s___m_n_t_o_p_s), describes the mount options associated
     with the filesystem.  It is formatted as a comma separated list of op-
     tions.  It contains at least the type of mount (see _f_s___t_y_p_e below) plus
     any additional options appropriate to the filesystem type.

     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 _q_u_o_t_a_._u_s_e_r and
     _q_u_o_t_a_._g_r_o_u_p 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 _/_t_m_p is stored in _/_v_a_r_/_q_u_o_t_a_s_/_t_m_p_._u_s_e_r, this location can
     be specified as:

           userquota=/var/quotas/tmp.user

     The type of the mount is extracted from the _f_s___m_n_t_o_p_s field and stored
     separately in the _f_s___t_y_p_e field (it is not deleted from the _f_s___m_n_t_o_p_s
     field).  If _f_s___t_y_p_e is ``rw'' or ``ro'' then the filesystem whose name is
     given in the _f_s___f_i_l_e field is normally mounted read-write or read-only on
     the specified special file.  If _f_s___t_y_p_e 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 _f_s___s_p_e_c
     and _f_s___t_y_p_e are unused.  If _f_s___t_y_p_e is specified as ``xx'' the entry is
     ignored.  This is useful to show disk partitions which are currently un-
     used.

     The fifth field, (_f_s___f_r_e_q), 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, (_f_s___p_a_s_s_n_o), 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 _f_s___p_a_s_s_n_o of 1, and other filesys-
     tems should have a _f_s___p_a_s_s_n_o 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 zero, a value of zero is returned and
     fsck will assume that the filesystem does not need to be checked.

     #define FSTAB_RW        "rw"    /* read-write device */
     #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;    /* type of filesystem */
             char    *fs_mntops;     /* comma separated mount options */
             char    *fs_type;       /* rw, ro, sw, or xx */
             int     fs_freq;        /* dump frequency, in days */
             int     fs_passno;      /* pass number on parallel dump */
     };

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

FFIILLEESS
     /etc/fstab  The file ffssttaabb resides in _/_e_t_c.

SSEEEE AALLSSOO
     getfsent(3)

HHIISSTTOORRYY
     The ffssttaabb file format appeared in 4.0BSD.

4th Berkeley Distribution        June 5, 1993                                2