1. Services down alert like Apache, MySQL, Exim
2. Exim alerts when queue goes beyond 1000, 2000, 5000 etc.
3. CPU, memory usage alerts
4. Monitoring single or multiple websites
5. Disk Space usage monitoring
6. High traffic alerts
and many more
Please contact me first as it is big setup and I will need to know how many servers you bring in to monitoring and how many alerts you wish to add on server, for sure it can not be done in $5 so do not directly purchase the gig.