FSTAB(4-SysV) RISC/os Reference Manual FSTAB(4-SysV)
NAME
fstab, mtab - static filesystem mounting table, mounted
filesystems table
SYNOPSIS
/etc/fstab
/etc/mtab
DESCRIPTION
The /etc/fstab file contains entries for filesystems and
disk partitions to mount using the mount(1M) command, which
is normally invoked during the system boot process. This
file is used by various utilities that mount, unmount, check
the consistency of, dump, and restore file systems. It is
also used by the system itself when locating the swap parti-
tion.
The /etc/mtab file contains entries for filesystems
currently mounted, and is read by programs using the rou-
tines described in getmntent(3). umount (see mount(1M))
removes entries from this file.
Each entry consists of a line of the form:
filesystem directory type options freq pass
filesystem
is the pathname of a block-special device, or the
name of a remote filesystem in host:pathname form.
directory
is the pathname of the directory on which to mount
the filesystem.
type is the filesystem type, which can be one of:
ffs | ufs | 4.3
to mount a block-special device structured
as a Fast File System partition. The first
syntax is preferred.
nfs to mount an exported NFS filesystem
swap to indicate a swap partition
ignore to have the mount command ignore the
current entry (good for noting disk parti-
tions that are not being used)
options contains a comma-separated list (no spaces) of
mounting options, some of which can be applied to
all types of filesystems, and others which only
apply to specific types.
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ffs options:
quota|noquota
Disk quotas are enforced or not
enforced, respectively. quotaon(1M)
enables disk quotas on file systems.
mtab(4) entries show the current state
of the quota sub-system on a particu-
lar file system. noquota is the
default.
nfs_sync|nfs_async
Typically, NFS performs synchronous
writes; however, performing asynchro-
nous writes can speed-up performance
tremendously. This option allows nfs
servers to control their local file
system behavior for NFS write
requests. Synchronous writes guaran-
tee the data has been written to disk
rather than guaranteeing that a server
has correctly received a write
request. This only becomes an issue
if a server crashes during a write.
See kopt (8) to change the global
default value. nfs_async is the
current default.
nfs options:
quota|noquota
quota(1) will/will not report disk
quotas/usage for this file system.
This may affect execution time for
large fstab(4) files. The default is
set to noquota for this reason.
bg|fg If the first attempt fails, retry in
the background, or, in the foreground.
(default=fg)
retry=n The number of times to retry the mount
operation. (default=0 in fg, 10000 in
bg)
rsize=n Set the read buffer size to n bytes.
wsize=n Set the write buffer size to n bytes.
timeo=n Set the NFS timeout to n tenths of a
second.
retrans=n
The number of NFS retransmissions.
port=n The server IP port number.
soft|hard
Return an error if the server does not
respond, or continue the retry request
until the server responds.
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intr Allow keyboard interrupts on hard
mounts.
secure Use a more secure protocol for NFS
transactions.
acregmin=n
Hold cached attributes for at least n
seconds after file modification.
acregmax=n
Hold cached attributes for no more
than n seconds after file modifica-
tion.
acdirmin=n
Hold cached attributes for at least n
seconds after directory update.
acdirmax=n
Hold cached attributes for no more
than n seconds after directory update.
actimeo=n
Set min and max times for regular
files and directories to n seconds.
Common options:
ro|rw mount either read-only or read-write
nosuid setuid execution disallowed. suid is
the default and therefore not imple-
mented.
grpid Create files with BSD semantics for
propagation of the group ID. With this
option, files inherit the group ID of
the directory in which they are
created, regardless of the directory's
setgid bit.
noauto|hide
Do not mount this file system automat-
ically (using mount -a). Both are
equivalent although noauto is pre-
ferred and more common.
freq is the interval (in days) between dumps.
pass is the fsck(1M) pass in which to check the parti-
tion. Filesystems with the same pass number are
checked simultaneously in increasing order.
Filesystems with pass equal to 0 are not checked.
On a MIPS machine, it is usually optimal to set
the pass number of the root file system to 1 and
all others to 2. Very high configuration systems
may require splitting pass 2 into 2 and 3. Only
profiling of specific configurations can determine
the optimal pass number allocation algorithm. In
general, if different passes are used for the non-
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root file systems, similar length partitions should
be grouped together; and file systems on the same
drive should be separated. See the chapter "File
System Administration" in the System
Administrator's Guide for more details.
A pound-sign (#) as the first non-white character indicates
a comment line which is ignored by routines that read this
file. The order of records in /etc/fstab is important
because fsck, mount, and umount process the file sequen-
tially; an entry for a file system must appear after the
entry for any file system it is to be mounted on top of.
EXAMPLES
In this example, the /home/user directory is hard mounted
read-write over the NFS, along with additional swap space
in the form of a mounted swap file (see for details on
adding swap space):
/dev/hp0a / ffs rw,noquota 1 1
/dev/hp0b /usr ffs rw,noquota 1 1
example:/home/user /home/user nfs rw,hard,fg 0 0
/export/swap/myswap swap swap rw 0 0
FILES
/etc/fstab
/etc/mtab
SEE ALSO
getmntent(3), fstab(4), mtab(4).
fsck(1M), mount(1M), quotacheck(1M), quotaon(1M) in the Sys-
tem Administrator's Reference Manual.
quota(1) in the User's Reference Manual.
"File System Administration" in the System Administrator's
Guide.
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