Swapon is used to specify devices on which paging and swapping are to take place.
The device or file used is given by the
specialfile parameter. It may be of the form
-L label or
-U uuid to indicate a device by label or uuid.
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:
Tag
Description
-a
All devices marked as swap swap devices in
/etc/fstab are made available, except for those with the noauto option.
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.
-h
Provide help
-L label
Use the partition that has the specified
label. (For this, access to
/proc/partitions is needed.)
-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. Higher numbers indicate higher
priority. 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.
-s
Display swap usage summary by device. Equivalent to "cat /proc/swaps".
Not available before Linux 2.1.25.
-U uuid
Use the partition that has the specified
uuid. (For this, access to
/proc/partitions is needed.)
-v
Be verbose.
-V
Display version
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.