1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)swapon.8 8.1 (Berkeley) 6/5/93 33.\" $FreeBSD: src/sbin/swapon/swapon.8,v 1.15.2.2 2001/12/14 15:17:56 ru Exp $ 34.\" 35.Dd June 5, 1993 36.Dt SWAPON 8 37.Os 38.Sh NAME 39.Nm swapon 40.Nd "specify additional device for paging and swapping" 41.Sh SYNOPSIS 42.Nm 43.Fl a 44.Nm 45.Ar special_file ... 46.Sh DESCRIPTION 47.Nm Swapon 48is used to specify additional devices on which paging and swapping 49are to take place. 50The system begins by swapping and paging on only a single device 51so that only one disk is required at bootstrap time. 52Calls to 53.Nm 54normally occur in the system multi-user initialization file 55.Pa /etc/rc 56making all swap devices available, so that the paging and swapping 57activity is interleaved across several devices. 58.Pp 59Normally, the first form is used: 60.Bl -tag -width indent 61.It Fl a 62All devices marked as ``sw'' 63swap devices in 64.Pa /etc/fstab 65are made available unless their ``noauto'' option is also set. 66.El 67.Pp 68The second form gives individual block devices as given 69in the system swap configuration table. The call makes only this space 70available to the system for swap allocation. 71.Sh SEE ALSO 72.Xr swapon 2 , 73.Xr fstab 5 , 74.Xr init 8 , 75.Xr pstat 8 , 76.Xr rc 8 , 77.Xr vnconfig 8 78.Sh FILES 79.Bl -tag -width "/dev/{ad,da}?s?b" -compact 80.It Pa /dev/{ad,da}?s?b 81standard paging devices 82.It Pa /dev/vn0b 83vnode disk paging device 84.It Pa /etc/fstab 85ASCII filesystem description table 86.It Pa /etc/vntab 87ASCII vnode file table 88.El 89.Sh BUGS 90There is no way to stop paging and swapping on a device. 91It is therefore not possible to dismount swap devices which are 92mounted during system operation. 93.Sh HISTORY 94The 95.Nm 96command appeared in 97.Bx 4.0 . 98