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28 .\" @(#)swapon.8 8.1 (Berkeley) 6/5/93
29 .\" $FreeBSD: src/sbin/swapon/swapon.8,v 1.15.2.2 2001/12/14 15:17:56 ru Exp $
35 .Nm swapon , swapoff , swapctl
36 .Nd "specify devices for paging and swapping"
38 .Nm swapon Fl aeiq | Ar
39 .Nm swapoff Fl aq | Ar
52 utilities are used to control swap devices in the system.
53 At boot time all swap entries in
55 are added automatically when the system goes multi-user.
56 Swap devices use a fixed interleave; the maximum number of devices
57 is specified by the kernel configuration option
59 which is typically set to 4.
60 There is no priority mechanism.
64 utility adds the specified swap devices to the system.
67 option is used, all swap devices in
69 will be added, unless their
74 option is used informational messages will not be
75 written to standard output when a swap device is added.
78 option is used, the device will be trimmed if
79 it supports trim and the trim_enabled sysctl is on.
82 option asks user confirmation before adding a swap device.
86 utility removes the specified swap devices from the system.
89 option is used, all swap devices in
91 will be removed, unless their
96 option is used informational messages will not be
97 written to standard output when a swap device is removed.
100 will fail and refuse to remove a swap device if there is insufficient
101 VM (memory + remaining swap devices) to run the system.
105 must move swapped pages out of the device being removed which could
106 lead to high system loads for a period of time, depending on how
107 much data has been swapped out to that device.
111 utility exists primarily for those familiar with other
114 used to add, remove, or list swap devices.
117 option is used differently in
119 and indicates that a specific list of devices should be added.
122 option indicates that a specific list should be removed.
129 operate on all swap entries in
131 which do not have their
135 Swap information can be generated using the
145 utility has the following options for listing swap:
146 .Bl -tag -width indent
148 Output values in human-readable form.
150 Output values in gigabytes.
152 Output values in kilobytes.
154 Output values in megabytes.
156 List the devices making up system swap.
158 Print a summary line for system swap.
160 Attempts to Trim the device if -[Aa] is used.
162 Asks user confirmation when -a 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