268a55bc98
device names "md" or "md[0-9]*" and a "file" option are specified in
/etc/fstab like this:
md none swap sw,file=/swap.bin 0 0
- Add GBDE/GELI encrypted swap space specification support, which
rc.d/encswap supported. The /etc/fstab lines are like the following:
/dev/ada1p1.bde none swap sw 0 0
/dev/ada1p2.eli none swap sw 0 0
.eli devices accepts aalgo, ealgo, keylen, and sectorsize as options.
swapctl(8) can understand an encrypted device in the command line
like this:
# swapctl -a /dev/ada2p1.bde
- "-L" flag is added to support "late" option to defer swapon until
rc.d/mountlate runs.
- rc.d script change:
rc.d/encswap -> removed
rc.d/addswap -> just display a warning message if $swapfile is defined
rc.d/swap1 -> renamed to rc.d/swap
rc.d/swaplate -> newly added to support "late" option
These changes alleviate a race condition between device creation/removal
and swapon/swapoff.
MFC after: 1 week
Reviewed by: wblock (manual page)
226 lines
5.2 KiB
Groff
226 lines
5.2 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)swapon.8 8.1 (Berkeley) 6/5/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd June 21, 2013
|
|
.Dt SWAPON 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm swapon , swapoff , swapctl
|
|
.Nd "specify devices for paging and swapping"
|
|
.Sh SYNOPSIS
|
|
.Nm swapon
|
|
.Oo Fl F Ar fstab
|
|
.Oc
|
|
.Fl aLq | Ar
|
|
.Nm swapoff
|
|
.Oo Fl F Ar fstab
|
|
.Oc
|
|
.Fl aLq | Ar
|
|
.Nm swapctl
|
|
.Op Fl AghklmsU
|
|
.Oo
|
|
.Fl a Ar
|
|
|
|
|
.Fl d Ar
|
|
.Oc
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm swapon , swapoff
|
|
and
|
|
.Nm swapctl
|
|
utilities are used to control swap devices in the system.
|
|
At boot time all swap entries in
|
|
.Pa /etc/fstab
|
|
are added automatically when the system goes multi-user.
|
|
Swap devices use a fixed interleave; the maximum number of devices
|
|
is specified by the kernel configuration option
|
|
.Dv NSWAPDEV ,
|
|
which is typically set to 4.
|
|
There is no priority mechanism.
|
|
.Pp
|
|
The
|
|
.Nm swapon
|
|
utility adds the specified swap devices to the system.
|
|
If the
|
|
.Fl a
|
|
option is used, all swap devices in
|
|
.Pa /etc/fstab
|
|
will be added, unless their
|
|
.Dq noauto
|
|
or
|
|
.Dq late
|
|
option is also set.
|
|
If the
|
|
.Fl L
|
|
option is specified,
|
|
swap devices with the
|
|
.Dq late
|
|
option will be added as well as ones with no option.
|
|
If the
|
|
.Fl q
|
|
option is used,
|
|
informational messages will not be
|
|
written to standard output when a swap device is added.
|
|
.Pp
|
|
The
|
|
.Nm swapoff
|
|
utility removes the specified swap devices from the system.
|
|
If the
|
|
.Fl a
|
|
option is used, all swap devices in
|
|
.Pa /etc/fstab
|
|
will be removed, unless their
|
|
.Dq noauto
|
|
or
|
|
.Dq late
|
|
option is also set.
|
|
If the
|
|
.Fl L
|
|
option is specified,
|
|
swap devices with the
|
|
.Dq late
|
|
option will be removed as well as ones with no option.
|
|
If the
|
|
.Fl q
|
|
option is used,
|
|
informational messages will not be
|
|
written to standard output when a swap device is removed.
|
|
Note that
|
|
.Nm swapoff
|
|
will fail and refuse to remove a swap device if there is insufficient
|
|
VM (memory + remaining swap devices) to run the system.
|
|
The
|
|
.Nm swapoff
|
|
utility
|
|
must move swapped pages out of the device being removed which could
|
|
lead to high system loads for a period of time, depending on how
|
|
much data has been swapped out to that device.
|
|
.Pp
|
|
Other options supported by both
|
|
.Nm swapon
|
|
and
|
|
.Nm swapoff
|
|
are as follows:
|
|
.Bl -tag -width indent
|
|
.It Fl F Ar fstab
|
|
Specify the
|
|
.Pa fstab
|
|
file to use.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Nm swapctl
|
|
utility exists primarily for those familiar with other
|
|
.Bx Ns s
|
|
and may be
|
|
used to add, remove, or list swap devices.
|
|
Note that the
|
|
.Fl a
|
|
option is used differently in
|
|
.Nm swapctl
|
|
and indicates that a specific list of devices should be added.
|
|
The
|
|
.Fl d
|
|
option indicates that a specific list should be removed.
|
|
The
|
|
.Fl A
|
|
and
|
|
.Fl U
|
|
options to
|
|
.Nm swapctl
|
|
operate on all swap entries in
|
|
.Pa /etc/fstab
|
|
which do not have their
|
|
.Dq noauto
|
|
option set.
|
|
.Pp
|
|
Swap information can be generated using the
|
|
.Xr swapinfo 8
|
|
utility,
|
|
.Nm pstat
|
|
.Fl s ,
|
|
or
|
|
.Nm swapctl
|
|
.Fl l .
|
|
The
|
|
.Nm swapctl
|
|
utility has the following options for listing swap:
|
|
.Bl -tag -width indent
|
|
.It Fl h
|
|
Output values in human-readable form.
|
|
.It Fl g
|
|
Output values in gigabytes.
|
|
.It Fl k
|
|
Output values in kilobytes.
|
|
.It Fl m
|
|
Output values in megabytes.
|
|
.It Fl l
|
|
List the devices making up system swap.
|
|
.It Fl s
|
|
Print a summary line for system swap.
|
|
.Pp
|
|
The
|
|
.Ev BLOCKSIZE
|
|
environment variable is used if not specifically
|
|
overridden.
|
|
512 byte blocks are used by default.
|
|
.El
|
|
.Sh FILES
|
|
.Bl -tag -width ".Pa /dev/{ad,da}?s?b" -compact
|
|
.It Pa /dev/{ad,da}?s?b
|
|
standard paging devices
|
|
.It Pa /dev/md?
|
|
memory disk devices
|
|
.It Pa /etc/fstab
|
|
.Tn ASCII
|
|
file system description table
|
|
.El
|
|
.Sh DIAGNOSTICS
|
|
These utilities may fail for the reasons described in
|
|
.Xr swapon 2 .
|
|
.Sh SEE ALSO
|
|
.Xr swapon 2 ,
|
|
.Xr fstab 5 ,
|
|
.Xr init 8 ,
|
|
.Xr mdconfig 8 ,
|
|
.Xr pstat 8 ,
|
|
.Xr rc 8
|
|
.Sh HISTORY
|
|
The
|
|
.Nm swapon
|
|
utility appeared in
|
|
.Bx 4.0 .
|
|
The
|
|
.Nm swapoff
|
|
and
|
|
.Nm swapctl
|
|
utilities appeared in
|
|
.Fx 5.1 .
|