systemd-swap

Smart dynamic swap management for Linux, written in Rust.

Overview

systemd-swap automatically configures the best swap strategy for your system:

• Auto-detection: Smartly chooses between Zswap and Zram based on your filesystem.
• Zswap + SwapFC: (Default for Btrfs/Ext4/XFS) Uses compressed RAM cache + dynamic swap files. Most efficient for desktops.
• Zram: (Default for others) Uses compressed RAM block device. Good for systems without disk swap support.
• Dynamic Scaling: Creates swap files on-demand, starting small and growing as needed.

Installation

Arch Linux / BigLinux / Manjaro...

cd pkgbuild
makepkg -si

Manual Build

Requirements: Rust 1.70+, btrfs-progs, util-linux

cargo build --release
sudo make install
sudo systemctl enable --now systemd-swap

Usage

Check status:

systemd-swap status

Reload configuration:

sudo systemctl restart systemd-swap

Configuration

Configuration is located at /etc/systemd/swap.conf.

Common Options

Change Swap Mode:

# Modes: auto, zswap+swapfc, zram, manuall
swap_mode=auto

Customize Zram Size:

zram_size=50%

Customize Swap File Location:

swapfc_path=/mnt/data/swapfile

See /usr/share/systemd-swap/swap-default.conf for all available options and defaults.

Features

• Zero Configuration: Works out of the box for most systems.
• Sparse Files: Swap files use zero disk space until data is actually written (when using Zswap).
• MGLRU Support: Integrates with Multi-Gen LRU (Kernel 6.1+) to prevent thrashing.
• Zram Writeback: Can offload cold pages from Zram to disk.

License

GPL-3.0-or-later