systemd boot vs grub: Performance or simplicity, what matters more? We explore these aspects for both bootloaders.

systemd-boot (formerly Gummiboot) and GRUB (GRand Unified Bootloader) are two distinct boot loaders for Linux systems, each with its own design philosophy and target use cases.

systemd-boot

systemd-boot is a lightweight UEFI boot manager. It is designed for simplicity and speed, integrating well with systems that already utilize the systemd init system.

• UEFI Only: It exclusively supports systems booting in UEFI mode. It does not support legacy BIOS systems.
• Simplicity: Configuration is managed through simple text files located in the EFI System Partition (ESP). Boot entries (.conf files) are placed in /boot/loader/entries/ or /efi/loader/entries/, and global settings in /boot/loader/* or /efi/loader/*.
• Automatic Detection: It can automatically detect bootable EFI executables, including Linux kernels (if built as EFI executables or via a stub loader), the Windows Boot Manager, and the macOS bootloader, simplifying multi-boot setups on UEFI systems.
• Kernel Location: Traditionally, systemd-boot expects kernels and initramfs images to reside on the ESP. However, it also supports the Boot Loader Specification, allowing kernels to be on other partitions if a Boot Loader Interface-compatible stub is used or if the XBOOTLDR partition scheme is followed.
• Minimalism: It focuses on booting the operating system and lacks the complex scripting capabilities, extensive theming options, or built-in filesystem drivers (beyond FAT for the ESP) found in GRUB.
• Integration: Managed using the bootctl command-line utility for installing, updating, and querying the boot loader status.

GRUB (GRand Unified Bootloader)

GRUB is a powerful and highly versatile bootloader. It is the most common bootloader for many Linux distributions due to its broad compatibility and feature set.

• Broad Compatibility: Supports both UEFI and legacy BIOS systems, making it suitable for a wider range of hardware.
• Filesystem Support: GRUB has its own drivers for many filesystems (e.g., ext4, XFS, Btrfs, NTFS). This allows it to load kernels and initramfs images from partitions formatted with these filesystems, not just the ESP.
• Advanced Configuration and Customization: Configuration is primarily handled via the file, which is typically generated by scripts like update-grub or grub-mkconfig based on settings in /etc/default/grub and scripts in /etc/grub.d/. It offers extensive customization options, including theming, menu entries, and scripting capabilities through its own shell.
• Feature-Rich: Includes features like chainloading other bootloaders, a rescue mode for system recovery, support for encrypted /boot partitions (with appropriate modules), Secure Boot compatibility (when signed), and network booting (PXE).
• Complexity: Its power and flexibility come with increased configuration complexity compared to systemd-boot. Manual editing of is generally discouraged.

Key Differences Summarized

• Firmware Support:
  • systemd-boot: UEFI only.
  • GRUB: UEFI and Legacy BIOS.
• Configuration Method:
  • systemd-boot: Simple, human-readable text files directly in the ESP. Easier for direct manual management.
  • GRUB: Complex , usually auto-generated. More powerful but less straightforward for manual edits.
• Kernel/Initramfs Location:
  • systemd-boot: Prefers kernels on the ESP or relies on Boot Loader Specification for other locations.
  • GRUB: Can load kernels from various filesystems on different partitions due to its built-in filesystem drivers.
• Features & Flexibility:
  • systemd-boot: Minimalist, focused on booting EFI executables.
  • GRUB: Rich feature set including rescue console, scripting, extensive theming, and broader OS/filesystem support.
• Ease of Use for Target Scenario:
  • systemd-boot: Generally simpler for modern UEFI-only systems with straightforward boot requirements and kernels on the ESP.
  • GRUB: More versatile for complex scenarios, legacy systems, or when advanced boot options are necessary, but with a steeper learning curve for detailed configuration.

In essence, systemd-boot is favored for its simplicity and directness on modern UEFI systems, especially by users who prefer manual, transparent configuration. GRUB remains the go-to for its broad compatibility, robust feature set, and ability to handle more complex boot scenarios across a wider variety of hardware and system setups.