System monitoring

Check the overall health of a Debian/Ubuntu Linux machine. This is a read-only sweep: it observes and reports, it does not change anything.

Monitoring checklist

1. CPU usage: check load and top processes.
2. Memory: RAM and swap usage (free -h).
3. Disk: free space and I/O (df -h).
4. Network: traffic and connectivity.
5. Processes: running processes and resource consumption.
6. Services: status of critical units (systemctl --failed, systemctl is-active <service>).
7. Temperatures: system temperatures if sensors are available.
8. Logs: recent errors or warnings (journalctl -p 3 -b).

Provide a summary of system health and flag any concerns. Suggest follow-up if issues are found; for a routine fix-up, the maintenance workflow is the next step.