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Install zRAM on Debian(8)
#!/bin/bash
#
not_root() {
echo "ERROR: You have to be root to execute this script"
exit 1
}
zram_exists() {
echo "ERROR: /etc/init.d/zram already exists"
exit 1
}
# Check if user is root
[ $EUID != 0 ] && not_root
# Check if zram file already exists
[ -f /etc/init.d/zram ] && zram_exists
cat >/etc/init.d/zram <<EOL
#!/bin/sh
### BEGIN INIT INFO
# Provides: zram
# Required-Start: $local_fs
# Required-Stop: $local_fs
# Default-Start: S
# Default-Stop: 0 1 6
# Short-Description: Use compressed RAM as in-memory swap
# Description: Use compressed RAM as in-memory swap
### END INIT INFO
# Author: Antonio Galea <antonio.galea@gmail.com>
# Thanks to Przemysław Tomczyk for suggesting swapoff parallelization
FRACTION=75
MEMORY=\`perl -ne'/^MemTotal:\s+(\d+)/ && print \$1*1024;' < /proc/meminfo\`
CPUS=\`grep -c processor /proc/cpuinfo\`
SIZE=\$(( MEMORY * FRACTION / 100 / CPUS ))
case "\$1" in
"start")
param=\`modinfo zram|grep num_devices|cut -f2 -d:|tr -d ' '\`
modprobe zram \$param=\$CPUS
for n in \`seq \$CPUS\`; do
i=\$((n - 1))
echo \$SIZE > /sys/block/zram\$i/disksize
mkswap /dev/zram\$i
swapon /dev/zram\$i -p 10
done
;;
"stop")
for n in \`seq \$CPUS\`; do
i=$((n - 1))
swapoff /dev/zram\$i && echo "disabled disk \$n of \$CPUS" &
done
wait
sleep .5
modprobe -r zram
;;
*)
echo "Usage: \`basename \$0\` (start | stop)"
exit 1
;;
esac
EOL
chmod +x /etc/init.d/zram
insserv zram
/etc/init.d/zram start
exit 0
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