AutoMon

It is a centralized monitoring solution and alert triggering by using database mail. This needs two databases to be created called DBAData and DBAData_Archive, the current data will be stored in DBAData and the archive will be stored in Archive database. The monitoring works based on the master table data DBA_All_servers and SVR_status column should be ‘running’.

I suggest to have a dedicated VM or Instance to have this databases, so that it is easy to have firewall opened to DMZ or different subnet servers from one source. I have started using this from 2008, when we have no tool to invest cost and even some places, we will have limited licence and those will monitor only important servers.

Benefit of AutoMon:
This will collect the data by linked server and send a consolidated report by email based on the threshold. The archive data can been integrated with SSRS and the report can be pulled to view as graph and trend of last week/month/year data of disk, CPU, RAM etc.

The full script can be downloaded from my GitHub https://github.com/muthukkumarankaliyamoorthy/SQL-AutoMon-free-monitoring-tool

More Details about each script can be read here: https://sqlserverblogforum.com/category/automon/

Looking forward to help on this.

My latest scripts are updated in GitHub.