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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"
43 .Nm swapon Fl aeq | Ar
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.
83 option is used, the device will be trimmed if
84 it supports trim and the trim_enabled sysctl is on.
88 utility removes the specified swap devices from the system.
91 option is used, all swap devices in
93 will be removed, unless their
98 option is used informational messages will not be
99 written to standard output when a swap device is removed.
102 will fail and refuse to remove a swap device if there is insufficient
103 VM (memory + remaining swap devices) to run the system.
107 must move swapped pages out of the device being removed which could
108 lead to high system loads for a period of time, depending on how
109 much data has been swapped out to that device.
113 utility exists primarily for those familiar with other
116 used to add, remove, or list swap devices.
119 option is used differently in
121 and indicates that a specific list of devices should be added.
124 option indicates that a specific list should be removed.
131 operate on all swap entries in
133 which do not have their
137 Swap information can be generated using the
147 utility has the following options for listing swap:
148 .Bl -tag -width indent
150 Output values in human-readable form.
152 Output values in gigabytes.
154 Output values in kilobytes.
156 Output values in megabytes.
158 List the devices making up system swap.
160 Print a summary line for system swap.
162 Attempts to Trim the device if -[Aa] is used.
166 environment variable is used if not specifically
168 1K blocks are used by default.
171 .Bl -tag -width ".Pa /dev/{ad,da}?s?b" -compact
172 .It Pa /dev/{ad,da}?s?b
173 standard paging devices
175 vnode disk paging device
177 ASCII filesystem description table
179 ASCII vnode file table
182 These utilities may fail for the reasons described in
200 utilities appeared in
202 and were later ported to