fstab(5) [ultrix man page]
fstab(5) File Formats Manual fstab(5) Name fstab - file containing static information about known file systems Description The file contains descriptive information about the known file systems. By convention, is created and maintained as a read-only file by the system administrator. Each file system is described by its own line within The order of these lines and the file systems they repre- sent is important because and sequentially process in the performance of their tasks. The format of each file system description in is as follows: spec:file:type:freq:passno:name:options The meanings of these fields are: spec The block special file name of the device on which the file system is located. It can also be a network name for such as or file The pathname of the directory on which the file system is mounted. type How the file system is mounted. The ways in which a file system can be mounted are: rw - mount the file system read-write ro - mount the file system read only rq - mount the file system read-write with quotas sw - make the special file part of the swap space xx - ignore the entry freq The frequency (in days) with which the command dumps the rw, ro, and rq file systems. passno The order in which the command checks the rw, ro, and rq file systems at reboot time. name The name of the file system type. File systems can have the following types: ufs -- ULTRIX file system and nfs -- SUN Network file system. options The options field. This field contains an arbitrary string meaningful only when mounting file systems with the specified file system type name, such as NFS. The specific options are described in the reference pages. Special actions occur for file systems of type sw and rq at system boot time. File systems of type sw are made part of the swap space by the command and disk quotas are automatically processed by the command and then enabled by the command for rq file systems. Examples Here is a sample file: /dev/ra0a:/:rw:1:1:ufs:: /dev/ra1g:/usr:rw:1:2:ufs:: /@bigvax:/bigvax:rw:0:0:nfs:: /usr/uws2.0@bigvax:/usr/uws2.0:rw:0:0:nfs:soft,bg,nosuid: /usr/dec@bigvax:/usr/dec:rw:0:0:nfs:bg,soft,nosuid: /usr/pro/xyz@vax:/usr/pro/xyz:rw:0:0:nfs:bg,soft,intr,nosuid: The last three entries in the sample shown use NFS options as described in the reference page. Restrictions The passno field of the root file system should be specified as 1. Other file systems should have larger values. File systems on the same device should have distinct passno fields. File systems on different devices may have the identical passno fields to allow them to be simultaneously checked. All field delimiters (:) must exist within each file system description; only the options field may not be present. However, only the fields spec and type are meaningful to sw file systems and only the type field is meaningful to xx file systems. The file system description within should be parsed only through use of the routines. Files File system information file See Also getfsent(3x), dump(8), fsck(8), mount(8), mount(8nfs), mount(8ufs) quotacheck(8), quotaon(8), swapon(8) fstab(5)
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FSTAB(5) File Formats Manual FSTAB(5) NAME
fstab - static information about the filesystems SYNOPSIS
#include <fstab.h> DESCRIPTION
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) sequen- tially 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 filesystem. For swap partitions, this field should be specified as ``none''. The third field, fs_vfstype, describes the type of the filesystem. The system currently supports only two types of filesystems: ufs a local UNIX filesystem swap a disk partition to be used for swapping 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. If the option ``quotas'' is specified, the filesystem is automatically processed by the quotacheck(8) command, and user disk quotas are enabled with quotaon(8). Filesystem quotas are maintained in the file named quotas located at the root of the associated filesystem. This restriction on the location of the quotas file is needlessly imposed by the kernel but may be lifted in the future. Thus, if the user quota file for /tmp is stored in /var/quotas/tmp.user, this location can be specified as: quotas=/var/quotas/tmp.user 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 unused. 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(8) 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 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. If the sixth field is not present or 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_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 fstab is to use the routines getfsent(3), getfsspec(3), getfstype(3), and getfsfile(3). FILES
/etc/fstab The file fstab resides in /etc. SEE ALSO
getfsent(3) HISTORY
The fstab file format appeared in 4.0BSD. 4.4 Berkeley Distribution January 15, 1996 FSTAB(5)