1.\" Copyright (c) 1980, 1991 Regents of the University of California. 2.\" 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 6.3 (Berkeley) 3/16/91 33.\" 34.Dd March 16, 1991 35.Dt SWAPON 8 36.Os BSD 4 37.Sh NAME 38.Nm swapon 39.Nd "specify additional device for paging and swapping" 40.Sh SYNOPSIS 41.Nm swapon 42.Fl a 43.Nm swapon 44.Ar special_file ... 45.Sh DESCRIPTION 46.Nm Swapon 47is used to specify additional devices on which paging and swapping 48are to take place. 49The system begins by swapping and paging on only a single device 50so that only one disk is required at bootstrap time. 51Calls to 52.Nm swapon 53normally occur in the system multi-user initialization file 54.Pa /etc/rc 55making all swap devices available, so that the paging and swapping 56activity is interleaved across several devices. 57.Pp 58Normally, the first form is used: 59.Bl -tag -width Ds 60.It Fl a 61All devices marked as ``sw'' 62swap devices in 63.Pa /etc/fstab 64are made available. 65.El 66.Pp 67The second form gives individual block devices as given 68in the system swap configuration table. The call makes only this space 69available to the system for swap allocation. 70.Sh SEE ALSO 71.Xr swapon 2 , 72.Xr fstab 8 73.Xr init 8 74.Xr rc 8 75.Sh FILES 76.Bl -tag -width /dev/[ru][pk]?b -compact 77.It Pa /dev/[ru][pk]?b 78standard paging devices 79.It Pa /etc/fstab 80ascii filesystem description table 81.El 82.Sh BUGS 83There is no way to stop paging and swapping on a device. 84It is therefore not possible to make use of devices which may be 85dismounted during system operation. 86.Sh HISTORY 87The 88.Nm 89command appeared in 90.Bx 4.0 . 91