zRam is a virtual memory compression using block devices named /dev/zram using a fast compression algorithm (LZ4) that compress the least recently used (LRU) or inactive space in the memory allows the GNU/Linux kernel to free up more memory with less performance hit.
zRam is greatly increased the available amount of memory by compressing memory without swap disks/partition. It is recommended for the user to use zRam instead of not use/disable the swap to prevent out of memory (OOM) killer. Create a zRam block devices Load the zRam modules to the kernel using modprobe:
sudo modprobe zramSet the zRam extremely fast compression algorithm using lz4:
sudo sh -c "echo 'lz4' > /sys/block/zram0/comp_algorithm"
Set 2 Gigabyte available zRam disk space for swap:
sudo sh -c "echo '2G' > /sys/block/zram0/disksize"
Create a swap on zRam block devices:
sudo mkswap --label zram0 /dev/zram0
Enable the zRam block devices for swapping with high priority:
sudo swapon --priority 100 /dev/zram0
Automatically activate zRam swap at startup Create a systemd service (zram.service) using a text editor such as nano:
sudo nano /etc/systemd/system/zram.service
Add following to the zram.service:
[Unit]
Description=zRam block devices swapping
[Service]
Type=oneshot
ExecStart=/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:
sudo systemctl enable zram
Disable zRam block devices To disable the zRam block devices swapping, run following commands:
sudo swapoff /dev/zram0
Remove the zRam module from the kernel:
sudo rmmod zram
Disable the zram.service from automatically run at startup:
sudo systemctl disable zram.service