adminDatabase Architecture Mental Model Checklist for System Admins
A database is not just a place where an application stores data. It is a system with clients, connections, users, permissions, queries, indexes, memory, storage, logs, backups and recovery rules.
Core principle
When a database problem happens, do not think only about tables. Think about the full path: application request, database connection, authentication, query execution, storage engine, disk, locks, logs and response.
Checklist
- Identify which application uses the database.
- Identify database host, port and engine.
- Identify database name and user.
- Check how the application connects.
- Check whether the issue is connection, permission, query, storage or resource related.
- Map tables that are critical to the application.
- Check backup and restore method.
- Check database logs.
- Check server CPU, RAM and disk.
- Document the database dependency map.
Reusable lesson
This model applies to WordPress, n8n, analytics tools, dashboards, SaaS apps, APIs and internal automation systems.
When to Use This Checklist
Use this checklist when learning how databases support websites, apps, APIs and automation systems from an infrastructure perspective.
Required Tools
Database access, application config, SSH access, MySQL or MariaDB, database logs, backup method, server monitoring
Before You Start
Do not troubleshoot database errors only from the application screen. Map the full database path first.
Structured Checklist Steps
- Identify application dependency.
- Identify database host and port.
- Identify database engine.
- Identify database user.
- Check connection path.
- Classify the failure layer.
- Map critical tables.
- Check logs.
- Check server resources.
- Document dependency map.
Verification Steps
- Database host is known.
- Connection method is known.
- Critical database user is known.
- Failure layer is classified.
- Backup and recovery path is documented.
Rollback Plan
If a database investigation leads to risky changes, stop and create a database backup before editing users, tables, schema or configuration.
Common Mistakes
- Thinking every database issue is a password issue.
- Ignoring database host and port.
- No dependency map.
- No restore plan.
- Changing tables before backup.
Related Commands
grep DB_ wp-config.php
sudo systemctl status mysql
sudo ss -tulpn | grep 3306
mysql -u db_user -p -e "SHOW DATABASES;"
mysqladmin -u root -p status
df -h
free -h