Install zram, Compressed swap space, 2GB memory total

echo "IyEvYmluL2Jhc2gKY29yZXM9JChucHJvYyAtLWFsbCkKbW9kcHJvYmUgenJhbSBudW1fZGV2aWNlcz0kY29yZXMKCnN3YXBvZmYgLWEKCnRvdGFsbWVtPWBmcmVlIHwgZ3JlcCAtZSAiXk1lbToiIHwgYXdrICd7cHJpbnQgJDJ9J2AKbWVtPSQoKCAoJHRvdGFsbWVtIC8gJGNvcmVzKSogMTAyNCApKQoKY29yZT0wCndoaWxlIFsgJGNvcmUgLWx0ICRjb3JlcyBdOyBkbwogIGVjaG8gJG1lbSA+IC9zeXMvYmxvY2svenJhbSRjb3JlL2Rpc2tzaXplCiAgbWtzd2FwIC9kZXYvenJhbSRjb3JlCiAgc3dhcG9uIC1wIDUgL2Rldi96cmFtJGNvcmUKICBsZXQgY29yZT1jb3JlKzEKZG9uZQo=" | base64 --decode > /usr/bin/zram.sh
chmod +x /usr/bin/zram.sh

Add '/usr/bin/zram.sh &' before 'exit 0' in 'rc.local':

cat /etc/rc.local

#!/bin/sh -e
#
# rc.local
#
# This script is executed at the end of each multiuser runlevel.
# Make sure that the script will "exit 0" on success or any other
# value on error.
#
# In order to enable or disable this script just change the execution
# bits.
#
# By default this script does nothing.

# Print the IP address
_IP=$(hostname -I) || true
if [ "$_IP" ]; then
  printf "My IP address is %s\n" "$_IP"
fi
/usr/bin/zram.sh &

exit 0

Appendix. The content of zram.sh:

#!/bin/bash
cores=$(nproc --all)
modprobe zram num_devices=$cores

swapoff -a

totalmem=`free | grep -e "^Mem:" | awk '{print $2}'`
mem=$(( ($totalmem / $cores)* 1024 ))

core=0
while [ $core -lt $cores ]; do
  echo $mem > /sys/block/zram$core/disksize
  mkswap /dev/zram$core
  swapon -p 5 /dev/zram$core
  let core=core+1
done

Related:
https://www.kernel.org/doc/Documentation/blockdev/zram.txt