MNTENT(5,F) AIX Technical Reference MNTENT(5,F)
-------------------------------------------------------------------------------
mntent, mtab
PURPOSE
Contains information about mounted file systems.
SYNOPSIS
#include <mntent.h>
DESCRIPTION
The file /etc/mtab describes the file systems currently mounted on the local
machine. It is a symbolic link to a local-only file. To find out about file
systems mounted on other sites in a TCF cluster, specify a specific site's
<LOCAL>/mtab file to the setmtnent routine.
The file /etc/mtab is created at system-startup time to include the root and
<LOCAL> file systems by the setmnt command. When run, the mount command adds
entries to the /etc/mtab file, and the umount command removes entries.
The /etc/mtab file consists of a number of lines of the form:
fsname dir type opts freq passno flags gfs pack time
For example,
/dev/xy0a/ufs rw,noquota 1 2 40 1 7 604161472
The entries in this file are accessed using the routines in getmntent, which
returns a structure of the following form:
struct mntent {
char *mnt_fsname; /* file system name */
char *mnt_dir; /* file system path prefix */
char *mnt_type; /* ufs, nfs */
char *mnt_opts; /* ro, quota, etc. */
int mnt_freq; /* dump frequency, in days */
int mnt_checkno; /* check number for parallel fsck */
char *mnt_flags; /* file system flags */
gfs_t mnt_gfs; /* global file system numbers */
pckno_t mnt_pack; /* pack number */
long mnt_time; /* time when mounted */
};
There is one entry per line in the file and the fields are separated by blanks.
The mnt_opts field consists of a string of options separated by commas. Some
of the options are common to all file system types while others only make sense
Processed November 7, 1990 MNTENT(5,F) 1
MNTENT(5,F) AIX Technical Reference MNTENT(5,F)
for a single file system type. For more information on the options available
with the mount command, see AIX Operating System Commands Reference.
The mnt_type field determines how the mnt_fsname and mnt_opts fields will be
interpreted. Below is a list of file system types currently supported and the
way in which each interprets these fields:
+-----------+------------+----------------------------------------------------+
|ufs | mnt_fsname | Must be a block special device. |
+-----------+------------+----------------------------------------------------+
| | mnt_opts | Valid options are ro, rw, suid, nosuid, quota, |
| | | noquota. |
+-----------+------------+----------------------------------------------------+
|nfs | mnt_fsname | The path on the server of the directory to be |
| | | served. |
+-----------+------------+----------------------------------------------------+
| | mnt_opts | Valid options are ro, rw, suid, nosuid, hard, |
| | | soft, bg, fg, retry, rsize, wsize, timeo, retrans, |
| | | port, intr. |
+-----------+------------+----------------------------------------------------+
The mnt_freq field indicates how often each partition should be dumped by the
dumpbsd command, and also triggers the w option of the dumpbsd command
indicating the file systems that should be dumped. Most systems set the
mnt_freq field to 1, indicating that the file systems are dumped each day.
The mnt_checkno field is used by the disk consistency check program fsck to
control simultaneous checking of file systems during a reboot. To avoid having
two file systems checked simultaneously, make sure the values of mnt_checkno
are the same.
The mnt_flags field corresponds to the s_flags field in the file system super
block. For more information, see "fs."
The mnt_gfs field indicates the global file system number for the file system.
The mnt_pack field indicates the global file system pack number for the file
system.
The mnt_time field indicates the time the file system was mounted by specifying
the number of seconds since Jan 1, 1970 00:00:00 GMT.
FILE
/etc/mtab
RELATED INFORMATION
In this book: "getmntent, setmntent, addmntent, endmntent, hasmntopt."
The fsck, mount, quotacheck, and quotaon commands in AIX Operating System
Commands Reference.
Processed November 7, 1990 MNTENT(5,F) 2