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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
80 option is used informational messages will not be
81 written to standard output when a swap device is added.
85 utility removes the specified swap devices from the system.
88 option is used, all swap devices in
90 will be removed, unless their
95 option is used informational messages will not be
96 written to standard output when a swap device is removed.
99 will fail and refuse to remove a swap device if there is insufficient
100 VM (memory + remaining swap devices) to run the system.
104 must move swapped pages out of the device being removed which could
105 lead to high system loads for a period of time, depending on how
106 much data has been swapped out to that device.
108 Other options supported by both
113 .Bl -tag -width indent
122 utility exists primarily for those familiar with other
125 used to add, remove, or list swap devices.
128 option is used differently in
130 and indicates that a specific list of devices should be added.
133 option indicates that a specific list should be removed.
140 operate on all swap entries in
142 which do not have their
146 Swap information can be generated using the
156 utility has the following options for listing swap:
157 .Bl -tag -width indent
159 Output values in human-readable form.
161 Output values in gigabytes.
163 Output values in kilobytes.
165 Output values in megabytes.
167 List the devices making up system swap.
169 Print a summary line for system swap.
173 environment variable is used if not specifically
175 512 byte blocks are used by default.
178 .Bl -tag -width ".Pa /dev/{ad,da}?s?b" -compact
179 .It Pa /dev/{ad,da}?s?b
180 standard paging devices
185 file system description table
188 These utilities may fail for the reasons described in
206 utilities appeared in