As I have been using the GPL project NetSaint from 2001 in order to monitor my IT infrastructure (currently the project is named Nagios) please find some info about the Industry Standard in Monitoring IT Infrastructure.

Nagios is a powerful monitoring system that enables organizations to identify and resolve IT infrastructure problems before they affect critical business processes.

Designed with scalability and flexibility in mind, Nagios gives you the peace of mind that comes from knowing your organization's business processes won't be affected by unknown outages.

Nagios is a powerful tool that provides you with instant awareness of your organization's mission-critical IT infrastructure. Nagios allows you to detect and repair problems and mitigate future issues before they affect end-users and customers.

By using Nagios, you can:

• Plan for infrastructure upgrades before outdated systems cause failures
• Respond to issues at the first sign of a problem
• Automatically fix problems when they are detected
• Coordinate technical team responses
• Ensure your organization's SLAs are being met
• Ensure IT infrastructure outages have a minimal effect on your organization's bottom line
• Monitor your entire infrastructure and business processes

How It Works

Monitoring

IT staff configure Nagios to monitor critical IT infrastructure components, including system metrics, network protocols, applications, services, servers, and network infrastructure. 

Alerting

Nagios sends alerts when critical infrastructure components fail and recover, providing administrators with notice of important events. Alerts can be delivered via email, SMS, or custom script.

Response

IT staff can acknowledge alerts and begin resolving outages and investigating security alerts immediately. Alerts can be escalated to different groups if alerts are not acknowledged in a timely manner.

Reporting

Reports provide a historical record of outages, events, notifications, and alert response for later review. Availability reports help ensure your SLAs are being met.

Maintenance

Scheduled downtime prevents alerts during scheduled maintenance and upgrade windows.

Planning

Trending and capacity planning graphs and reports allow you to identify necessary infrastructure upgrades before failures occur.