Veeam Monitor 3.0 Free Edition for ESXi
Free real-time monitoring for your ESXi with Veeam Monitor 3.0 free edition.
With the Veeam Monitor 3.0 you get the following features:
Performance monitoring
Correlation of event and performance data
User interface optimized for monitoring
Advanced alerting and flexible alarms
Scalable architecture
Support for multiple VirtualCenters
Easy to deploy and use
Simple upgrade to the full version
See their site for more details.