如何在SCOM中覆盖‘计算机不可达’监视器？

Absolutely, you can override the 'Computer Not Reachable' monitor to trigger alerts for your groups—let’s break down why your alerts might not be firing and how to fix this properly.

1. Verify You’re Targeting the Correct Monitor & Scope #

First, double-check you’re working with the right monitor:

• Navigate to Authoring > Monitors > Windows Computers > Entity Health > Availability > Computer Not Reachable in the SCOM console. This is the standard monitor for detecting offline Windows computers.
• When creating the override, ensure you’re applying it to your specific target group (not all computers) and saving it to a custom management package—never save overrides to default sealed management packages, as this causes issues with future updates.
• Confirm the computers you’re testing are actually members of the group you targeted with the override.

2. Check Override Configuration Parameters #

Default settings might delay or block alerts—here’s what to adjust:

• Enable Parameter: Make sure you’ve set Enable to True in the override. If the monitor was disabled at a higher level (like the parent class), your override needs to explicitly re-enable it.
• Detection Timing: By default, the monitor waits 5 minutes (300 seconds) and checks 3 times before marking a computer as unreachable. If you want faster alerts, override Interval Seconds (e.g., set to 60) and Unhealthy Threshold (e.g., set to 2) to shrink the detection window.
• Alert Generation: Ensure the monitor is configured to generate alerts—check that Generate Alert is set to True in the override properties.

3. Validate Alert Notifications & Subscriptions #

Even if the monitor triggers an alert, you might miss it if notifications are misconfigured:

• This monitor generates a state-based alert, not a rule-based alert. Double-check your notification subscription includes state changes from this monitor (filter by monitor name "Computer Not Reachable").
• Confirm the subscription targets the correct recipients and uses a working notification channel (email, SMS, etc.).

4. Test & Diagnose Further #

If you’re still not seeing alerts, run these quick checks:

• Manual Test: Disconnect a test computer from the network, then check its state in Monitoring > Windows Computers. If the computer’s availability state turns critical but no alert fires, the issue is with alert routing, not the monitor itself.
• Check Operations Manager Logs: On your SCOM management server, open Event Viewer and navigate to Applications and Services Logs > Operations Manager. Look for events related to the monitor (Event IDs 1102 or 1201) to see if it’s detecting the unreachable state.
• Agent Health: Ensure the SCOM agent on the test computer is healthy and communicating with the management server. If the agent is already offline, the monitor might not be able to report the state change.

Once you’ve worked through these steps, your override should correctly trigger alerts when computers go offline.

内容的提问来源于stack exchange，提问作者Dragan