In this lesson, you will learn how to bridge the gap between your mdadm RAID arrays and your system’s notification workflows so you never miss a critical drive failure.
The Role of mdadm --monitor
While mdadm manages your arrays, it also includes a built-in monitoring daemon designed to watch the health of your RAID devices. When an array enters a "degraded" state—such as when a disk fails—the daemon can trigger an alert, ensuring you aren't waiting for a catastrophe to realize you have lost redundancy.
To start this monitoring process, you generally run mdadm in monitor mode. For example:
sudo mdadm --monitor --mail=admin@example.com --scan --daemonise
In this command:
--monitor: Tellsmdadmto watch the arrays for state changes.--mail: Specifies the recipient for system alerts.--scan: Instructs it to monitor all arrays listed in your/etc/mdadm/mdadm.conffile.--daemonise: Runs the process in the background.
Integrating with Infrastructure Notifications
Simply emailing a root account often results in missed warnings. To integrate this into professional infrastructure workflows, you should configure a "program" to run whenever an event occurs. You can modify your /etc/mdadm/mdadm.conf file to include a PROGRAM directive:
# /etc/mdadm/mdadm.conf
MAILADDR admin@example.com
PROGRAM /usr/local/bin/raid-alert-script.sh
When an event triggers, mdadm passes the event type and the device name to your script as arguments. Your script can then parse these inputs to send the alert to a modern notification pipeline, such as Slack, PagerDuty, or a centralized logging server (like syslog).
By delegating the notification logic to a script, you move beyond simple emails. You gain the ability to categorize events—for instance, treating a "RebuildStarted" event as a low-priority log entry, but treating a "DeviceFailed" event as an immediate, high-priority incident that triggers an automated SMS or chat notification. This proactive approach ensures your storage health is always visible within your wider operations dashboard.
Key Takeaway: Use the mdadm --monitor daemon combined with custom handler scripts to turn raw hardware failures into actionable infrastructure alerts.