GRUB (GRand Unified Bootloader) and systemd-boot (formerly Gummiboot) are both bootloaders for Linux systems, but they cater to different needs and environments.
GRUB (GRand Unified Bootloader)
GRUB is a powerful and highly versatile bootloader. It is the de facto standard for many Linux distributions.
- Versatility: Supports booting from a wide array of filesystems (ext2/3/4, XFS, Btrfs, FAT, NTFS, etc.) and partition schemes (MBR and GPT).
- Compatibility: Works with both legacy BIOS systems and modern UEFI systems.
- Feature-rich: Offers extensive configurability, including themed menus, rescue mode, chainloading other bootloaders (like Windows Boot Manager), kernel parameter modification at boot time, and support for encrypted partitions (LUKS).
- Complexity: Its power comes with a degree of complexity. Configuration is typically managed through scripts (e.g.,
grub-mkconfig) and files like/etc/default/grub, which can be less intuitive for simple setups. - Widespread Support: Due to its long history and broad adoption, extensive documentation and community support are available.
systemd-boot
systemd-boot is a lightweight UEFI boot manager. It is part of the systemd suite but can be used independently.
- Simplicity: Designed to be minimal and straightforward. It reads simple, human-readable text files for boot entries from the EFI System Partition (ESP).
- UEFI-only: Exclusively for systems using UEFI firmware. It does not support legacy BIOS.
- ESP-centric: Kernels, initramfs images, and configuration files are typically stored directly on the ESP. This simplifies the boot process as systemd-boot doesn't need drivers for various filesystems; it relies on the UEFI firmware to access the FAT-formatted ESP.
- Easy Configuration: Boot entries are defined in
.conffiles in the/boot/loader/entries/directory (or equivalent path on the ESP). Kernel updates often involve simply copying the new kernel and initramfs to the ESP and updating or adding a new entry file. - Integration: Integrates well with other systemd tools, such as
bootctlfor managing boot entries and UEFI boot variables. - Limitations: Lacks advanced features like theming, extensive filesystem support (relies on UEFI for ESP access), or a sophisticated rescue shell found in GRUB. Primarily targets Linux systems.
Key Differences Summarized
- Firmware Support:
- GRUB: BIOS and UEFI
- systemd-boot: UEFI only
- Configuration:
- GRUB: More complex, often script-generated (e.g., ).
- systemd-boot: Simple text files directly on the ESP.
- Filesystem Handling:
- GRUB: Built-in drivers for many filesystems.
- systemd-boot: Relies on UEFI to access the ESP (typically FAT32); loads kernels from there.
- Feature Set:
- GRUB: Extensive (theming, rescue mode, cross-platform chainloading, etc.).
- systemd-boot: Minimalist, focused on booting Linux kernels from the ESP.
- Use Case Focus:
- GRUB: Suitable for complex setups, dual-booting with various OS (Windows, macOS), legacy systems, and users needing advanced boot options.
- systemd-boot: Ideal for modern UEFI-based Linux systems where simplicity, speed, and direct ESP management are preferred. It is often favored in distributions that heavily leverage the systemd ecosystem.
In essence: Choose GRUB for maximum compatibility, features, and flexibility, especially if dealing with non-UEFI systems or complex multi-boot scenarios. Opt for systemd-boot for a simpler, faster, and more modern boot experience on UEFI-only Linux systems, particularly if you prefer manual or straightforward configuration and appreciate integration with the systemd project.
