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Create zRam a Memory Compression on Arch Linux www.techrapid.co.uk /linux/arch-linux/create-zram-memory-compression-on-arch-linux

zRam is a virtual memory compression using block devices named /dev/zram using a fast compression algorithmthat compress the least recently used (LRU) or inactive space in the memory allows the GNU/Linux kernel to freeup more memory with less performance hit.

zRam is greatly increasing the available amount of memory without swap disks/partition. It is recommendedfor user to use zRam instead of not using swap or swap on slow disks.

Create a zRam block devices

Load the zRam modules to the kernel using modprobe:

Shell

1 sudo modprobe zram

Set the zRam extremely fast compression algorithm using lz4:Shell

1 sudo sh -c "echo 'lz4' > /sys/block/zram0/comp_algorithm"

Set 2 Gigabyte available zRam disk space for swap:Shell

1 sudo sh -c "echo '2G' > /sys/block/zram0/disksize"

Create a swap on zRam block devices:Shell

1 sudo mkswap --label zram0 /dev/zram0

Enable the zRam block devices for swapping with high priority:Shell

1 sudo swapon --priority 100 /dev/zram0

Aut omatically activate zRam swap at startup

Create a systemd service ( zram.service ) using a text editor such as nano :

Shell

1 sudo nano /etc/systemd/system/zram.service

Add following to the zram.service:

Shell

http://www.techrapid.co.uk/linux/arch-linux/create-zram-memory-compression-on-arch-linuxhttp://www.techrapid.co.uk/linux/arch-linux/create-zram-memory-compression-on-arch-linux

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[Unit]Description=zRam block devices swapping[Service]Type=oneshotExecStart=/usr/bin/bash -c "modprobe zram && echo lz4 > /sys/block/zram0/comp_algorithm | echo 2G >/sys/block/zram0/disksize && mkswap --label zram0 /dev/zram0 && swapon --priority 100 /dev/zram0"ExecStop=/usr/bin/bash -c "swapoff /dev/zram0 && rmmod zram"RemainAfterExit=yes[Install]WantedBy=multi-user.target

Enable the zram.service to automatically run at startup:Shell

1 sudo systemctl enable zram

Disable zRam block devices

Disable the zRam block devices swapping:

Shell

1 sudo swapoff /dev/zram0

Remove the zRam module from the kernel:Shell

1 sudo rmmod zram

Disable the zram.service from automatically run at startup:Shell

1 sudo systemctl disable zram.service

See also

1. Zram or zswap section (Maximizing Performance) – ArchWiki

2. zram: Compressed RAM based block devices – Linux Kernel Documentation

3. Image by TobiasD / CC0 Public Domain

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