Swap

How to handle swappiness

Start top and press O then p to sort by swap.

top -c

Look to see if any swap is being used. si and so is swap in and swap out.

vmstat 1

To return swap to ram.

swapoff -a; swapon -a
(swapoff -a; swapon -a) & watch free -m

See swappiness value.

cat /proc/sys/vm/swappiness

To set swippiness value.

sudo sysctl vm.swappiness=0

sort processes on swap usage.

for PROCESS in /proc/*/; do   swapused=$(awk 'BEGIN { total = 0 } /^Swap:[[:blank:]]*[1-9]/ { total = total + $2 } END { print total }' ${PROCESS}/smaps 2>/dev/null || echo 0);   if [ $swapused -gt 0 ]; then     /bin/echo -e "${swapused}k\t$(cat ${PROCESS}/cmdline)";   fi; done | sort -nr

add swap on existing disk

dd if=/dev/zero of=/swapfile bs=1GB count=3
mkswap /swapfile
swapon /swapfile
chmod 0600 /swapfile
# /etc/fstab
/swapfile none swap sw 0 0