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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 .\" $DragonFly: src/sbin/swapon/swapon.8,v 1.4 2007/08/10 18:28:27 swildner Exp $
40 .Nm swapon , swapoff , swapctl
41 .Nd "specify devices for paging and swapping"
44 .Nm swapoff Fl aq | Ar
57 utilities are used to control swap devices in the system.
58 At boot time all swap entries in
60 are added automatically when the system goes multi-user.
61 Swap devices use a fixed interleave; the maximum number of devices
62 is specified by the kernel configuration option
64 which is typically set to 4.
65 There is no priority mechanism.
69 utility adds the specified swap devices to the system.
72 option is used, all swap devices in
74 will be added, unless their
79 option is used informational messages will not be
80 written to standard output when a swap device is added.
84 utility removes the specified swap devices from the system.
87 option is used, all swap devices in
89 will be removed, unless their
94 option is used informational messages will not be
95 written to standard output when a swap device is removed.
98 will fail and refuse to remove a swap device if there is insufficient
99 VM (memory + remaining swap devices) to run the system.
103 must move swapped pages out of the device being removed which could
104 lead to high system loads for a period of time, depending on how
105 much data has been swapped out to that device.
109 utility exists primarily for those familiar with other
112 used to add, remove, or list swap devices.
115 option is used differently in
117 and indicates that a specific list of devices should be added.
120 option indicates that a specific list should be removed.
127 operate on all swap entries in
129 which do not have their
133 Swap information can be generated using the
143 utility has the following options for listing swap:
144 .Bl -tag -width indent
146 Output values in human-readable form.
148 Output values in gigabytes.
150 Output values in kilobytes.
152 Output values in megabytes.
154 List the devices making up system swap.
156 Print a summary line for system swap.
160 environment variable is used if not specifically
162 1K blocks are used by default.
165 .Bl -tag -width ".Pa /dev/{ad,da}?s?b" -compact
166 .It Pa /dev/{ad,da}?s?b
167 standard paging devices
169 vnode disk paging device
171 ASCII filesystem description table
173 ASCII vnode file table
176 These utilities may fail for the reasons described in
194 utilities appeared in
196 and were later ported to