# for CentOS 6.6
( cd /etc/init.d; export $(grep ^proxy= /etc/yum.conf)>/dev/null; curl -LO ${proxy:+-x $proxy} https://gist.github.com/kou1okada/c22e32283c472490e214/raw/zram && chmod +x zram )
chkconfig --add zram
chkconfig zram on
/etc/init.d/zram loads below configuration files.
Example of configuration file:
# FACTOR=50 # Percentage to total memory for zram size (default: 50).
service zram {start|stop|restart|status}
| #!/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: An initscript for zram. | |
| # The official page of this script is below. | |
| # https://gist.github.com/kou1okada/c22e32283c472490e214 | |
| # This script uses below as a recerence. | |
| # https://github.com/mystilleef/FedoraZram | |
| # https://gist.github.com/jdef/8544249 | |
| # https://launchpad.net/ubuntu/+source/zram-config | |
| # https://extremeshok.com/5094/centos-6-x-rhce-6-redhat-6-zram-compression-compressed-swap-residing-in-ram-over-allocating-memory/ | |
| # This script is distributed under the GPLv2. | |
| # https://www.gnu.org/licenses/gpl-2.0.html | |
| ### END INIT INFO | |
| . /etc/init.d/functions | |
| RETVAL=0 | |
| is_running () { | |
| ls /sys/block/zram* >& /dev/null | |
| } | |
| start() { | |
| local FACTOR num_devices memtotal mem modparms | |
| if is_running; then | |
| echo -n "; zram already configured, aborting" | |
| return 1 | |
| fi | |
| [ -f /etc/sysconfig/zram ] && . /etc/sysconfig/zram | |
| : ${FACTOR:=50} | |
| num_devices=$(grep -c processor /proc/cpuinfo | sed 's/^0$/1/') | |
| if modinfo zram | grep -q ' zram_num_devices:' 2>/dev/null; then | |
| modparms+=( "zram_num_devices=${num_devices}" ) | |
| elif modinfo zram | grep -q ' num_devices:' 2>/dev/null; then | |
| modparams+=( "num_devices=${num_devices}" ) | |
| else | |
| echo -n "; 'modinfo zram' dose not have parm of zram_num_devices or num_devices, aborting" | |
| return 1 | |
| fi | |
| modprobe zram "${modparams[@]}" | |
| memtotal=$( free -b | awk '/^Mem:/ {print $2}' ) | |
| mem=$(( memtotal / num_devices * FACTOR / 100 )) | |
| for i in $( seq 0 $(( num_devices - 1 )) ); do | |
| grep -q lz4 "/sys/block/zram${i}/comp_algorithm" >&/dev/null \ | |
| && echo lz4>"/sys/block/zram${i}/comp_algorithm" | |
| echo $mem > "/sys/block/zram${i}/disksize" | |
| mkswap "/dev/zram${i}" > /dev/null | |
| swapon -p 5 "/dev/zram${i}" | |
| done | |
| } | |
| stop() { | |
| local i | |
| for i in $(awk '$1 ~ "^/dev/zram[0-9]+$" {print $1}' /proc/swaps); do | |
| swapoff "${i}" | |
| done | |
| if grep -q "^zram " /proc/modules; then | |
| sleep 1 | |
| rmmod zram | |
| fi | |
| } | |
| status() { | |
| local i compr orig ratio | |
| is_running || return 0 | |
| for i in /sys/block/zram*; do | |
| compr=$(< "${i}/compr_data_size" ) | |
| orig=$(< "${i}/orig_data_size" ) | |
| ratio=0 | |
| if (( 0 < $compr )); then | |
| ratio=$(awk "BEGIN{print ${orig}*100/${compr}; exit0}") | |
| fi | |
| echo -e "/dev/${i##*/}:\t${ratio}% (${orig} -> ${compr})" | |
| done | |
| } | |
| case "$1" in | |
| start) | |
| action "Starting zram" start | |
| ;; | |
| stop) | |
| action "Stopping zram" stop | |
| ;; | |
| restart) | |
| "$0" stop | |
| sleep 3 | |
| "$0" start | |
| ;; | |
| status) | |
| status | |
| ;; | |
| *) | |
| echo "Usage: $0 {start|stop|restart|status}" | |
| RETVAL=1 | |
| esac |