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Mattscreative edited this page Dec 5, 2025 · 2 revisions

Arch Linux Log Management Guide

Complete beginner-friendly guide to log management on Arch Linux, including journalctl, log rotation, log analysis, and log maintenance.

Table of Contents

  1. systemd Journal
  2. journalctl Usage
  3. Log Rotation
  4. Log Analysis
  5. Troubleshooting

systemd Journal

Journal Location

Journal files:

# Journal location
/var/log/journal/

# User journal
~/.local/share/journal/

Journal Configuration

Configure journal:

# Edit config
sudo vim /etc/systemd/journald.conf

Settings:

[Journal]
Storage=persistent
SystemMaxUse=1G
SystemKeepFree=2G

journalctl Usage

View Logs

Basic commands:

# All logs
journalctl

# Recent logs
journalctl -n 50

# Follow logs
journalctl -f

# Boot logs
journalctl -b

Filter Logs

Filter by:

# By service
journalctl -u service-name

# By priority
journalctl -p err

# By time
journalctl --since today
journalctl --since "2024-01-15 10:00:00"

Log Rotation

Journal Rotation

Configure rotation:

# Edit config
sudo vim /etc/systemd/journald.conf

Settings:

SystemMaxUse=1G
SystemKeepFree=2G
MaxRetentionSec=1month

Manual Rotation

Rotate logs:

# Rotate journal
sudo journalctl --rotate

# Vacuum old logs
sudo journalctl --vacuum-time=2weeks
sudo journalctl --vacuum-size=1G

Log Analysis

Search Logs

Search:

# Search text
journalctl | grep error

# Case insensitive
journalctl | grep -i error

# With context
journalctl | grep -A 5 -B 5 error

Export Logs

Export:

# Export to file
journalctl > logs.txt

# Export specific service
journalctl -u service-name > service-logs.txt

Troubleshooting

Logs Too Large

Clean logs:

# Check size
journalctl --disk-usage

# Vacuum
sudo journalctl --vacuum-time=1week

Missing Logs

Check configuration:

# Check journal config
cat /etc/systemd/journald.conf

# Check journal status
systemctl status systemd-journald

Summary

This guide covered systemd journal, journalctl usage, log rotation, log analysis, and troubleshooting.

Next Steps

This guide is based on the ArchWiki. For the most up-to-date information, always refer to the official ArchWiki.

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