How enable zram module on kernel (debian lik distro)?

zram.sh

#!/bin/bash
### BEGIN INIT INFO
# Provides: zram
# Required-Start:
# Required-Stop:
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Increased Performance In Linux With zRam (Virtual Swap Compressed in RAM)
# Description: Adapted from systemd scripts at https://github.com/mystilleef/FedoraZram
### END INIT INFO
# source: http://crunchbanglinux.org/forums/topic/15344/zram-a-good-idea/%EF%BB%BF
# see also: http://mystilleef.blogspot.com/2011/10/enable-zram-in-fedora.html
# https://weirdfellow.wordpress.com/2011/05/04/compressed-ram-with-zram/
# download: wget -c https://raw.github.com/gist/1571378 -O /etc/init.d/zram && chmod +x $_
# warning: try this before --> modprobe -nv zram
# /dev/zram0 none swap sw,pri=5 0 0

######################################################################################
# para sistemas debian puros, para ubuntu onde o init é diferente tente outros meios
# Make the script executable & add it to default run levels:

# sudo chmod +x /etc/init.d/zram
# sudo update-rc.d zram defaults

# After booting verify the module is loaded with:

# lsmod | grep zram

# para ubuntu faça:
# https://gist.github.com/1583992
# sudo add-apt-repository ppa:shnatsel/zram
# sudo apt-get update
# sudo apt-get install zramswap-enabler
# leia também: http://vtnc.org/1638
#################################################################

start() {
    # get the number of CPUs
    num_cpus=$(grep -c processor /proc/cpuinfo)
    # if something goes wrong, assume we have 1
    [ "$num_cpus" != 0 ] || num_cpus=1

    # set decremented number of CPUs
    decr_num_cpus=$((num_cpus - 1))

    # get the amount of memory in the machine
    mem_total_kb=$(grep MemTotal /proc/meminfo | grep -E --only-matching '[[:digit:]]+')
    mem_total=$((mem_total_kb * 1024))

    # load dependency modules
    modprobe zram num_devices=$num_cpus

    # initialize the devices
    for i in $(seq 0 $decr_num_cpus); do
    echo $((mem_total / num_cpus)) > /sys/block/zram$i/disksize
    done

    # Creating swap filesystems
    for i in $(seq 0 $decr_num_cpus); do
    mkswap /dev/zram$i
    done

    # Switch the swaps on
    for i in $(seq 0 $decr_num_cpus); do
    swapon -p 100 /dev/zram$i
    done
}

stop() {
    # get the number of CPUs
    num_cpus=$(grep -c processor /proc/cpuinfo)

    # set decremented number of CPUs
    decr_num_cpus=$((num_cpus - 1))

    # Switching off swap
    for i in $(seq 0 $decr_num_cpus); do
    if [ "$(grep /dev/zram$i /proc/swaps)" != "" ]; then
    swapoff /dev/zram$i
    sleep 1
    fi
    done

    sleep 1
    rmmod zram
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    restart)
        stop
        sleep 3
        start
        ;;
    *)
        echo "Usage: $0 {start|stop|restart}"
        RETVAL=1
esac
exit $RETVAL

For multicore systems:

• for linux < 3.15,configure one zram swap per cpu core.
• for Linux >= 3.15, set maxs equal to the number of cores.

In this later case, the script cant be rewritten as the following:

case "$1" in
  "start")
    # load zram modules
    modprobe zram num_devices=1
    echo 4 > /sys/block/zram0/max_comp_streams
    echo $((8 * 1000 * 1000 * 1000 / 3)) > /sys/block/zram0/disksize
    mkswap /dev/zram0
    swapon -p 1000 /dev/zram0
    ;;
  "stop")
    swapoff /dev/zram0
    echo 1 > /sys/block/zram0/reset
    modprobe -r zram
    ;;
  *)
    echo "Usage: $(basename $0) (start | stop)"
    exit 1
    ;;
esac