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buster has been released
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'''zram''' (previously called '''compcache''') can create RAM based block devices. It is an experimental (staging) module of the Linux kernel since 3.2. | #language en '''zram''' (previously called '''compcache''') can create RAM based block devices. It is a module of the Linux kernel since 3.2. |
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== Background information == | See https://code.google.com/p/compcache/ and WikiPedia:Zram for more info. |
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* https://code.google.com/p/compcache/ * http://en.wikipedia.org/wiki/Zram |
== Installation and use == |
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== Startup script == | Starting at buster (released July 2019) it's possible to simply install the '''zram-tools''' package and customize '''/etc/default/zramswap''' for your needs. |
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Copy the following script to ''/etc/init.d/zram'': | For systems using a standard SysV-based init system, it's possible to copy the following script to ''/etc/init.d/zram'': |
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#!/bin/bash | #! /bin/sh # Author: Antonio Galea <antonio.galea@gmail.com> # # Thanks to Przemysław Tomczyk for suggesting swapoff parallelization # Distributed under the GPL version 3 or later, see terms at # https://gnu.org/licenses/gpl-3.0.txt |
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# Description: Use compressed RAM as in-memory swap | # Description: Use compressed RAM as in-memory swap |
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# Author: Antonio Galea <antonio.galea@gmail.com> |
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MEMORY=`perl -ne'/^MemTotal:\s+(\d+)/ && print $1*1024;' < /proc/meminfo` CPUS=`grep -c processor /proc/cpuinfo` SIZE=$(( MEMORY * FRACTION / 100 / CPUS )) |
MEMORY=$(perl -ne '/^MemTotal:\s+(\d+)/ && print $1*1024' < /proc/meminfo) CPUS=$(nproc) SIZE=$((MEMORY * FRACTION / 100 / CPUS)) |
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"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 done sleep .5 modprobe -r zram ;; *) echo "Usage: `basename $0` (start | stop)" exit 1 ;; |
start) param=$(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 --priority 10 done ;; stop) for n in $(seq $CPUS) do i=$((n - 1)) swapoff /dev/zram$i && echo "zram: disabled disk $n of $CPUS" & done wait sleep .5 modprobe --remove zram ;; *) echo "Usage: $(basename $0) (start | stop)" exit 1 ;; |
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# End of file |
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then instruct you system to start it at boot time, with the command | then make the script executable: |
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insserv zram | chmod +x /etc/init.d/zram |
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then instruct your system to start it at boot time, with the command (skip this on systemd) {{{ apt-get install insserv insserv zram }}} |
zram (previously called compcache) can create RAM based block devices. It is a module of the Linux kernel since 3.2.
See https://code.google.com/p/compcache/ and Zram for more info.
Installation and use
Starting at buster (released July 2019) it's possible to simply install the zram-tools package and customize /etc/default/zramswap for your needs.
For systems using a standard SysV-based init system, it's possible to copy the following script to /etc/init.d/zram:
# Author: Antonio Galea <antonio.galea@gmail.com> # # Thanks to Przemysław Tomczyk for suggesting swapoff parallelization # Distributed under the GPL version 3 or later, see terms at # https://gnu.org/licenses/gpl-3.0.txt ### BEGIN INIT INFO # Provides: zram # Required-Start: $local_fs # Required-Stop: $local_fs # Default-Start: S # Default-Stop: 0 1 6 # Short-Description: Use compressed RAM as in-memory swap # Description: Use compressed RAM as in-memory swap ### END INIT INFO FRACTION=75 MEMORY=$(perl -ne '/^MemTotal:\s+(\d+)/ && print $1*1024' < /proc/meminfo) CPUS=$(nproc) 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 --priority 10 done ;; stop) for n in $(seq $CPUS) do i=$((n - 1)) swapoff /dev/zram$i && echo "zram: disabled disk $n of $CPUS" & done wait sleep .5 modprobe --remove zram ;; *) echo "Usage: $(basename $0) (start | stop)" exit 1 ;; esac # End of file
then make the script executable:
chmod +x /etc/init.d/zram
then instruct your system to start it at boot time, with the command (skip this on systemd)
apt-get install insserv insserv zram