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clarify systemd section
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Deletions are marked like this. | Additions are marked like this. |
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= ZRam = |
#language en |
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* http://en.wikipedia.org/wiki/Zram | * WikiPedia:Zram |
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Copy the following script to /etc/init.d/zram: | Copy the following script to ''/etc/init.d/zram'': |
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## /etc/init.d/zram #!/bin/bash |
#!sh #!/bin/sh |
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# Description: Use compressed RAM as in-memory swap | # Description: Use compressed RAM as in-memory swap |
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# Thanks to Przemysław Tomczyk for suggesting swapoff parallelization # Distributed under the GPL version 3 or above, see terms at # https://gnu.org/licenses/gpl-3.0.txt |
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CPUS=`grep -c processor /proc/cpuinfo` | CPUS=`nproc` |
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echo $SIZE > /sys/block/zram$i/disksize | echo $SIZE > /sys/block/zram$i/disksize |
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swapoff /dev/zram$i | swapoff /dev/zram$i && echo "disabled disk $n of $CPUS" & |
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wait | |
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then instruct you system to start it at boot time, with the command | then you may have to make the script executable: {{{ chmod +x /etc/init.d/zram }}} then instruct your system to start it at boot time, with the command |
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== NB! == For systems running systemd, the [[https://packages.ubuntu.com/zram-config|Ubuntu package zram-config]] should be upgraded to 0.3 and newer. |
zram (previously called compcache) can create RAM based block devices. It is an experimental (staging) module of the Linux kernel since 3.2.
Background information
Startup script
Copy the following script to /etc/init.d/zram:
#!/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 # Distributed under the GPL version 3 or above, see terms at # https://gnu.org/licenses/gpl-3.0.txt 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 -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
then you may have to make the script executable:
chmod +x /etc/init.d/zram
then instruct your system to start it at boot time, with the command
insserv zram
NB!
For systems running systemd, the Ubuntu package zram-config should be upgraded to 0.3 and newer.