zram configuration

This note was created on 2023-06-15
This note was last edited on 2024-01-14

=== Manually enable for current session ===
To set up one zstd compressed zram device with 8GiB capacity and a higher-than-normal priority:
# modprobe zram
# zramctl /dev/zram0 --algorithm zstd --size 8G
# mkswap -U clear /dev/zram0
# swapon --priority 100 /dev/zram0

To disable it again, either reboot or run:
# swapoff /dev/zram0
# modprobe -r zram

=== Using zram-generator ===
1. Install "systemd-zram-generator" package.
2. Create configuration file "/etc/systemd/zram-generator.conf":
   ~~~
   [zram0]
   zram-size = ram / 2
   compression-algorithm = zstd
   swap-priority = 100
   fs-type = swap
   ~~~
3. Reload daemons:
   # systemctl daemon-reload
4. Enable and start the service:
   # systemctl enable --now systemd-zram-setup@zram0.service
5. Check if zram is working:
   # systemctl status systemd-zram-setup@zram0.service
   # zramctl

=== Disable zram on Fedora ===
Just uninstall "zram-generator-defaults":
# dnf remove zram-generator-defaults

To enable again - install the same package back.