systemd-analyze

Overview

systemd-analyze diagnoses boot performance and unit graphs: how long boot took, which units delayed it, whether unit files are valid, and whether calendar/timer expressions parse. First tool when “the box boots slowly”.

Syntax

systemd-analyze [options] [subcommand]

Common Subcommands

Subcommand	Description
time	Firmware/loader/kernel/userspace timings
blame	Units sorted by time to start
critical-chain	Critical path to default target
plot > boot.svg	SVG timeline
verify UNIT…	Static unit file checks
calendar EXPR	Explain calendar schedule
security UNIT	Sandbox exposure score (newer)
dot	Dependency graph (graphviz)

Examples with Explanations

Boot timings

systemd-analyze time
systemd-analyze blame | head
systemd-analyze critical-chain

Plot

systemd-analyze plot > /tmp/boot.svg
# open in a browser

Verify units after editing

systemd-analyze verify /etc/systemd/system/myapp.service

Calendar expressions (timers)

systemd-analyze calendar 'Mon..Fri *-*-* 09:00:00'
systemd-analyze calendar 'weekly'

Security profile (where available)

systemd-analyze security ssh.service | head

Notes & Pitfalls

• First boot after kernel update can skew blame times.
  
• Network mounts and cloud-init often dominate critical-chain.
  
• Containers without systemd won’t produce meaningful host boot data.

Related Commands

• systemctl
  
• journalctl -b
  
• systemd-run
  
• bootctl — EFI bootloader (where applicable)

Additional Resources

• man systemd-analyze