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28 .\" @(#)swapon.8 8.1 (Berkeley) 6/5/93
35 .Nm swapon , swapoff , swapctl
36 .Nd "specify devices for paging and swapping"
58 utilities are used to control swap devices in the system.
59 At boot time all swap entries in
61 are added automatically when the system goes multi-user.
62 Swap devices use a fixed interleave; the maximum number of devices
63 is specified by the kernel configuration option
65 which is typically set to 4.
66 There is no priority mechanism.
70 utility adds the specified swap devices to the system.
73 option is used, all swap devices in
75 will be added, unless their
85 option will be added as well as ones with no option.
89 informational messages will not be
90 written to standard output when a swap device is added.
94 utility removes the specified swap devices from the system.
97 option is used, all swap devices in
99 will be removed, unless their
107 swap devices with the
109 option will be removed as well as ones with no option.
113 informational messages will not be
114 written to standard output when a swap device is removed.
117 will fail and refuse to remove a swap device if there is insufficient
118 VM (memory + remaining swap devices) to run the system.
122 must move swapped pages out of the device being removed which could
123 lead to high system loads for a period of time, depending on how
124 much data has been swapped out to that device.
126 Other options supported by both
131 .Bl -tag -width indent
140 utility exists primarily for those familiar with other
143 used to add, remove, or list swap devices.
146 option is used differently in
148 and indicates that a specific list of devices should be added.
151 option indicates that a specific list should be removed.
158 operate on all swap entries in
160 which do not have their
164 Swap information can be generated using the
174 utility has the following options for listing swap:
175 .Bl -tag -width indent
177 Output values in human-readable form.
179 Output values in gigabytes.
181 Output values in kilobytes.
183 Output values in megabytes.
185 List the devices making up system swap.
187 Print a summary line for system swap.
191 environment variable is used if not specifically
193 512 byte blocks are used by default.
196 .Bl -tag -width ".Pa /dev/{ad,da}?s?b" -compact
197 .It Pa /dev/{ad,da}?s?b
198 standard paging devices
203 file system description table
206 These utilities may fail for the reasons described in
224 utilities appeared in