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swapon(8) [freebsd man page]

SWAPON(8)						    BSD System Manager's Manual 						 SWAPON(8)

NAME
swapon, swapoff, swapctl -- specify devices for paging and swapping SYNOPSIS
swapon [-F fstab] -aLq | file ... swapoff [-F fstab] -aLq | file ... swapctl [-AghklmsU] [-a file ... | -d file ...] DESCRIPTION
The swapon, swapoff and swapctl utilities are used to control swap devices in the system. At boot time all swap entries in /etc/fstab are added automatically when the system goes multi-user. Swap devices use a fixed interleave; the maximum number of devices is unlimited. There is no priority mechanism. The swapon utility adds the specified swap devices to the system. If the -a option is used, all swap devices in /etc/fstab will be added, unless their ``noauto'' or ``late'' option is also set. If the -L option is specified, swap devices with the ``late'' option will be added as well as ones with no option. If the -q option is used, informational messages will not be written to standard output when a swap device is added. The swapoff utility removes the specified swap devices from the system. If the -a option is used, all swap devices in /etc/fstab will be removed, unless their ``noauto'' or ``late'' option is also set. If the -L option is specified, swap devices with the ``late'' option will be removed as well as ones with no option. If the -q option is used, informational messages will not be written to standard output when a swap device is removed. Note that swapoff will fail and refuse to remove a swap device if there is insufficient VM (memory + remaining swap devices) to run the system. The swapoff utility must move swapped pages out of the device being removed which could lead to high system loads for a period of time, depending on how much data has been swapped out to that device. Other options supported by both swapon and swapoff are as follows: -F fstab Specify the fstab file to use. The swapctl utility exists primarily for those familiar with other BSDs and may be used to add, remove, or list swap devices. Note that the -a option is used differently in swapctl and indicates that a specific list of devices should be added. The -d option indicates that a spe- cific list should be removed. The -A and -U options to swapctl operate on all swap entries in /etc/fstab which do not have their ``noauto'' option set. Swap information can be generated using the swapinfo(8) utility, pstat -s, or swapctl -l. The swapctl utility has the following options for listing swap: -h Output values in human-readable form. -g Output values in gigabytes. -k Output values in kilobytes. -m Output values in megabytes. -l List the devices making up system swap. -s Print a summary line for system swap. The BLOCKSIZE environment variable is used if not specifically overridden. 512 byte blocks are used by default. FILES
/dev/{ada,da}?s?b standard paging devices /dev/md? memory disk devices /etc/fstab ASCII file system description table DIAGNOSTICS
These utilities may fail for the reasons described in swapon(2). SEE ALSO
swapon(2), fstab(5), init(8), mdconfig(8), pstat(8), rc(8) HISTORY
The swapon utility appeared in 4.0BSD. The swapoff and swapctl utilities appeared in FreeBSD 5.1. BSD
November 22, 2013 BSD

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SWAPON(8)						     Linux Programmer's Manual							 SWAPON(8)

NAME
swapon, swapoff - enable/disable devices and files for paging and swapping SYNOPSIS
/sbin/swapon [-h -V] /sbin/swapon -a [-v] [-e] /sbin/swapon [-v] [-p priority] specialfile ... /sbin/swapon [-s] /sbin/swapoff [-h -V] /sbin/swapoff -a /sbin/swapoff specialfile ... DESCRIPTION
Swapon is used to specify devices on which paging and swapping are to take place. Calls to swapon normally occur in the system multi-user initialization file /etc/rc making all swap devices available, so that the paging and swapping activity is interleaved across several devices and files. Normally, the first form is used: -h Provide help -V Display version -s Display swap usage summary by device. Equivalent to "cat /proc/swaps". Not available before Linux 2.1.25. -a All devices marked as ``swap'' swap devices in /etc/fstab are made available. Devices that are already running as swap are silently skipped. -e When -a is used with swapon, -e makes swapon silently skip devices that do not exist. -p priority Specify priority for swapon. This option is only available if swapon was compiled under and is used under a 1.3.2 or later kernel. priority is a value between 0 and 32767. See swapon(2) for a full description of swap priorities. Add pri=value to the option field of /etc/fstab for use with swapon -a. Swapoff disables swapping on the specified devices and files. When the -a flag is given, swapping is disabled on all known swap devices and files (as found in /proc/swaps or /etc/fstab). NOTE
You should not use swapon on a file with holes. Swap over NFS may not work. SEE ALSO
swapon(2), swapoff(2), fstab(5), init(8), mkswap(8), rc(8), mount(8) FILES
/dev/hd?? standard paging devices /dev/sd?? standard (SCSI) paging devices /etc/fstab ascii filesystem description table HISTORY
The swapon command appeared in 4.0BSD. Linux 1.x 25 September 1995 SWAPON(8)
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