Let’s say we have a computer booted over network and “/” is mounted over NFS.
The best sutuation is if we have enough RAM for all running programs. But sometimes we need to swap. No local disk – swap to remote.
Make an empty file (fill with zeros from /dev/zero):
root@kamera:/# dd if=/dev/zero of=/swap bs=1024 count=1048576
Simply swap to file over NFS may not work. So make a loop device:
root@kamera:/# losetup /dev/loop0 /swap
Make it suitable for swapping:
root@kamera:/# mkswap /dev/loop0 Setting up swapspace version 1, size = 1048572 KiB no label, UUID=931d6e04-78ec-41fd-ab2c-22522ac2711d
And swap:
root@kamera:/# swapon /dev/loop0
Write a script to make this swap permanent. /etc/init.d/swap may be like this:
#!/bin/sh
set -e
case "$1" in
start)
losetup /dev/loop0 /swap
swapon /dev/loop0
;;
stop)
swapoff /dev/loop0
losetup -d /dev/loop0
;;
restart)
swapoff /dev/loop0
swapon /dev/loop0
;;
*)
echo "Naudojimas: swap { start | stop | restart }" >&2
exit 1
;;
esac
exit 0
Make the file executable:
root@kamera:/# chmod +x /etc/init.d/swap
Enable it:
root@kamera:/# update-rc.d swap defaults
