Provided by: dphys-swapfile_20061020-4_all bug

NAME

       dphys-swapfile - set up, mount/unmount, and delete an swap file

SYNOPSIS

       dphys-swapfile setup|swapon|swapoff|uninstall

DESCRIPTION

       dphys-swapfile  computes  the  size for an optimal swap file (and resizes an existing swap
       file if necessary), mounts an swap file, unmounts it, and and delete it if not wanted  any
       more.

OPTIONS

       There is only one parameter, an command, which can be either of these:

       setup  Tells  dphys-swapfile  to  compute  the optimal swap file size and (re-)generate an
              fitting swap file. Default it 2 times RAM size. This can be called at boot time, so
              the  file allways stays the right size for current RAM, or run by hand whenever RAM
              size has changed.

       swapon and swapoff These run the swapon and swapoff commands on the  swapfile.  Note  that
              direct  swapon/off from /etc/fstab is not possible, as that is (at least on Debian)
              done in the same script that mounts /var (which is where the swap file most  likely
              resides). And we need to do our setup between those actions. So pass up /etc/fstab,
              and do our own swapon/off.

       uninstall
              Gets rid of an unwanted swap file, reclaiming the disk space.

CONFIG

       The config file /etc/dphys-swapfile allows the user to set up the working environment  for
       dphys-swapfile.

       This  config  file is a sh script fragment full of assignments, which is sourced. Standard
       sh syntax rules apply. Assignments are:

       CONF_SWAPFILE
              Set where the swap file should be placed. Defaults to  /var/swap.  It  is  unlikely
              that  you  will need to change this, unless you have very strange partitioning, and
              then you will most likely be using an swap partition anyway.

       CONF_SWAPSIZE
              Force file size to this. Default is 2*RAM size. This  is  unlikely  to  be  needed,
              unless in strange diskspace situations. Note that swap enabled and smaller than RAM
              causes kernal-internal VM trouble on random systems.

       CONF_SWAPFACTOR
              Set the relation between RAM and swap size. Must be an integer. Defaults to 2 which
              means swap size = 2 * RAM size

       CONF_MAXSWAP
              Set  maximum size of the swap file in MBytes. Defaults to 2048 which was the former
              kernel limit for the swapfile size and is now a limit to prevent unusual  big  swap
              files on systems with a lot of RAM.

FILES

       /etc/dphys-swapfile
              user config

       $CONF_SWAPFILE
              the swap file, target of the whole action (defaults to /var/swap)

EXAMPLES

       dphys-swapfile  is  usually  run  at  system  startup and shutdown from an /etc/init.d (or
       /etc/rc.d) script, such as this (minimal) one:

       #!/bin/sh
       # /etc/init.d/dphys-swapfile - automatically set up an swapfile
       # author franklin, last modification 2004.06.04
       # This script is copyright ETH Zuerich Physics Departement,
       #   use under either modified/non-advertising BSD or GPL license
       case "$1" in
         start)
           /sbin/dphys-swapfile setup
           /sbin/dphys-swapfile swapon
           ;;
         stop)
           /sbin/dphys-swapfile swapoff
           ;;
       esac
       exit 0

       If an sysadmin wants to have his swapfile in annother place,  say  /var/run/swap,  he  can
       use:

       In /etc/dphys-swapfile:

       CONF_SWAPFILE=/var/run/swap

AUTHOR

       franklin@phys.ethz.ch, http://www.phys.ethz.ch/~franklin/