Tips-&-Tricks.md

@@ -948,3 +948,55 @@ sudo zramctl --find --size 5G
     sudo mkswap /dev/zram0
     sudo swapon /dev/zram0
     ```
+
+To make the changes persist between reboots, create a service that executes the commands on boot.
+
+1. Add the commands of this post in a script that will be run at boot through a systemd service; and make it executable (`chmod +x`).
+
+2. Create a service “at boot”, with this script (just complete the ExecStart variable):
+
+    ```sh
+    #!/bin/sh
+    serviceName=run_at_boot
+    sudo tee /etc/systemd/system/$serviceName > /dev/null <<EOT
+    [Unit]
+    Description=run_at_boot
+
+    [Service]
+    ExecStart=<YOUR_SCRIPT_IN_ABSOLUTE_PATH>
+
+    [Install]
+    WantedBy=multi-user.target
+    EOT
+    sudo chmod +x /etc/systemd/system/$serviceName
+    sudo systemctl enable $serviceName
+    sudo systemctl status $serviceName
+    ```
+
+Alternatively, the [systemd zram-generator service can be configured]() (zram-generator systemd manual page: <https://raw.githubusercontent.com/systemd/zram-generator/master/man/zram-generator.conf.md>).
+
+- `zram-fraction` - Defines the scaling factor of the zram device's size with relation to the total usable RAM. Defaulted to *0.5*.
+- `max-zram-size` - Sets the limit on the zram device's size obtained by `zram-fraction`. Defaulted to *4096*.
+
+1. In `/usr/lib/systemd/zram-generator.conf.d/librem5.conf`:
+
+    ```conf
+    zram-fraction=2.0
+    max-zram-size=none
+    ```
+
+2. Run the command `systemctl restart systemd-zram-setup@zram0` to recreate the ZRAM device without rebooting.
+
+Alternative instructions to configure the systemd zram-generator service (Source: <https://www.ctrl.blog/entry/how-to-systemd-zram-generator.html>):
+
+1. Create the file `/etc/systemd/zram-generator.conf` and include the below configuration example. (You can also leave an empty file in this path to disable ZRAM).
+
+    ```conf
+    [zram0]
+    zram-fraction=0.5
+    max-zram-size=4096
+    ```
+
+    > The limits given above matches the default limits (50 % of available memory or 8 GB in MB). Change the limits to your preference. Keep in mind that the system can become unstable if you set it too high. I suggest staying with the default factor of 0.5 and increasing the max size to match your available system memory. For example, set `max-zram-size=8192` if you have 16 GB of RAM.
+
+2. > You can recreate the ZRAM device immediately without a reboot if you have enough physical memory to hold an uncompressed copy of all your currently compressed memory. The commands `free` and `zramctl` can help you determine the current memory pressure and compression ratio. Run the command `systemctl restart systemd-zram-setup@zram0.service` to recreate the ZRAM device without rebooting. However, the safest and quickest option is probably to save your work and reboot.
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