Custom counters are Windows Operating System or SQL Server metrics that are not monitored, by default, by SQL Diagnostic Manager. In addition to Windows Operating System and SQL Server metrics, you can enter T-SQL scripts to monitor any variable in your environment or select from a list of virtualization performance counters if you have monitored servers hosted on a virtual machine. Once added to the SQL Diagnostic Manager interface, you can monitor the results, view historical trending of the metric, configure alerts and receive notifications on them, and generate reports based on collected data.
Access the Add Custom Counter wizard
You can open the Add Custom Counter wizard by clicking> Custom Counters and selecting Add in the Custom Counters view.