FSTAB(4) FSTAB(4)
NAME
fstab - static information about filesystems
SYNOPSIS
#include <mntent.h>
DESCRIPTION
The file /etc/fstab describes the filesystems and swapping
partitions used by the local machine. The system
administrator can modify it with a text editor. It is read
by commands that mount, unmount, dump, restore, and check
the consistency of filesystems; also by the system when
providing swap space. The file consists of a number of
lines of the form:
fsname dir type opts freq passno
for example:
/dev/xy0a / efs rw,noquota 1 2
The entries from this file are accessed using the routines
in getmntent(3), which returns a structure of the following
form:
struct mntent {
char *mnt_fsname; /* filesystem name */
char *mnt_dir; /* filesystem path prefix */
char *mnt_type; /* efs, nfs, or ignore */
char *mnt_opts; /* rw, ro, noquota, quota, hard, soft */
int mnt_freq; /* dump frequency, in days */
int mnt_passno; /* pass number on parallel fsck */
};
Fields are separated by white space; a `#' as the first
non-white character indicates a comment.
The mnt_dir fields is the full path name of the directory to
be mounted on.
The mnt_type field determines how the mnt_fsname and
mnt_opts fields will be interpreted. Here is a list of the
filesystem types currently supported, and the way each of
them interprets these fields:
efs mnt_fsname must be a block special device.
nfs mnt_fsname the path on the server of the
directory to be served.
If the mnt_type is specified as ignore , then the entry is
ignored. This is useful to show disk partitions not
currently used.
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The mnt_opts field contains a list of comma-separated option
words. Some mnt_opts are valid for all filesystem types,
while others apply to a specific type only:
mnt_opts valid on all file systems (the default is
rw,suid):
rw read/write.
ro read-only.
suid set-uid execution allowed.
nosuid set-uid execution not allowed.
suid and nosuid are not supported.
raw=path
the filesystem's raw device interface pathname.
fsck fsck(1M) invoked with no filesystem arguments
should check this filesystem.
nofsck fsck(1M) should not check this filesystem by
default.
hide ignore this entry during a mount -a command to
allow you to define fstab entries for commonly
used filesystems you don't want to automatically
mount.
mnt_opts specific to nfs (NFS) file systems (the
defaults are:
fg,retry=1,timeo=7,retrans=4,port=NFSPORT,hard
with defaults for rsize and wsize set by the kernel):
bg if the first attempt fails, retry in the
background.
fg retry in foreground.
retry=n set number of failure retries to n.
rsize=n set read buffer size to n bytes.
wsize=n set write buffer size to n bytes.
timeo=n set NFS timeout to n tenths of a second.
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retrans=n set number of NFS retransmissions to n.
port=n set server IP port number to n.
soft return error if server doesn't respond.
hard retry request until server responds.
The bg option causes mount to run in the background if
the server's mountd(1M) does not respond. mount
attempts each request retry=n times before giving up.
Once the filesystem is mounted, each nfs request made
in the kernel waits timeo=n tenths of a second for a
response. If no response arrives, the time-out is
multiplied by 2 and the request is retransmitted. When
retrans=n retransmissions have been sent with no reply
a soft mounted filesystem returns an error on the
request and a hard mounted filesystem retries the
request. The number of bytes in a read or write
request can be set with the rsize and wsize options.
mnt_freq and mnt_passno are not supported.
FILES
/etc/fstab
SEE ALSO
getmntent(3), fsck(1M), mount(1M).
ORIGIN
Sun Microsystems, with changes for Silicon Graphics, Inc.
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