How To Configure ZRAM On Ubuntu Linux

Enabling ZRAM on Ubuntu

To enhance system performance, especially on low-memory systems, configuring ZRAM (Compressed RAM) can be highly beneficial. ZRAM allows you to trade some CPU power for additional RAM, which can significantly improve responsiveness in memory-constrained environments.

Installing ZRAM

To start, you need to install the zram-config package, which is available on all Debian-based distributions, including Ubuntu. Open a terminal and run the following commands:

sudo apt install zram-config
sudo systemctl enable zram-config
sudo systemctl start zram-config

After these steps, reboot your system to ensure the ZRAM configuration is applied.

Checking ZRAM Status

To verify that ZRAM is enabled and functioning correctly, use the zramctl utility:

zramctl

This command will display information about the ZRAM devices, including their size and usage.

Customizing ZRAM Configuration

By default, ZRAM is configured to use 50% of your available RAM. However, you can customize this setting to better suit your needs.

Changing ZRAM Size

To modify the size of the ZRAM device, you need to edit the init-zram-swapping script. Open the file in a text editor using:

sudo nano /usr/bin/init-zram-swapping

Locate the line that sets the ZRAM size, typically:

echo $mem > /sys/block/zram0/disksize

You can adjust this line to set a different percentage of your RAM. For example, to use 10% of your system memory, you would change the line to:

echo $((mem / 10)) > /sys/block/zram0/disksize

Save the file and reboot your system to apply the changes.

Changing the Compression Algorithm

ZRAM supports various compression algorithms, and you can change the default algorithm to optimize performance based on your system's workload. To list the available compression algorithms, run:

cat /sys/block/zram0/comp_algorithm

To change the compression algorithm, edit the init-zram-swapping script again and add the following lines below the existing echo command:

echo zstd > /sys/block/zram0/comp_algorithm

Replace zstd with any other supported algorithm if needed. Save the file and reboot your system.

Disabling Zswap

Zswap is another RAM cache solution that can interfere with ZRAM. To ensure Zswap is disabled, run:

sudo -s echo 0 > /sys/module/zswap/parameters/enabled

Reboot your system after making this change.

Monitoring and Adjusting Performance

After configuring ZRAM, it's crucial to monitor your system's performance under load. Use tools like zramctl and swapon to check the usage and performance of your ZRAM device:

zramctl
swapon

If you notice any performance issues, you may need to adjust the ZRAM size or compression algorithm. For example, if the system feels sluggish, you might have over-allocated memory to ZRAM, and reducing the size could help.

Advanced Configuration with zram-tools

For more advanced configurations, you can use the zram-tools package, which provides additional utilities and a simpler configuration file.

1. Install zram-tools:

   sudo apt-get install zram-tools
   

2. Edit the configuration file:

   sudo nano /etc/default/zramswap
   

3. Set the desired configuration:

For example, to use 10% of your system memory and the zstd compression algorithm, add the following lines:

ALGO=zstd
PERCENT=10

4. Reload the zram service:

   systemctl restart zramswap
   

5. Verify the configuration:

   swapon
   

This setup allows for a more straightforward configuration and can be particularly useful for fine-tuning your ZRAM settings.

By following these steps, you can effectively configure ZRAM on Ubuntu to enhance your system's performance, especially in scenarios where memory is limited.