$ sudo /sbin/dphys-swapfile setup
[sudo] password for drew:
computing size, drew@odroid:~$ sudo /sbin/dphys-swapfile swapon
/sbin/dphys-swapfile: ERROR: swap file /var/swap missing! you need to first run /sbin/dphys-swapfile setup to generate one
$
$ cat /etc/dphys-swapfile
/etc/dphys-swapfile - user settings for dphys-swapfile package
author Neil Franklin, last modification 2010.05.05
copyright ETH Zuerich Physics Departement
use under either modified/non-advertising BSD or GPL license
this file is sourced with . so full normal sh syntax applies
the default settings are added as commented out CONF_= lines
where we want the swapfile to be, this is the default
#CONF_SWAPFILE=/var/swap
set size to absolute value, leaving empty (default) then uses computed value
you most likely don’t want this, unless you have an special disk situation
#CONF_SWAPSIZE=
set size to computed value, this times RAM size, dynamically adapts,
guarantees that there is enough swap without wasting disk space on excess
#CONF_SWAPFACTOR=2
restrict size (computed and absolute!) to maximally this limit
can be set to empty for no limit, but beware of filled partitions!
this is/was a (outdated?) 32bit kernel limit (in MBytes), do not overrun it
but is also sensible on 64bit to prevent filling /var or even / partition
#CONF_MAXSWAP=2048