A count metric indicates the number of times a specific event happens within the server.
For example, the number of packets received on a network interface during a measurement interval is a count metric. Each measurement returns the count of the number of packets received during that measurement interval only. The sample contains the number of occurrences, whether the measurement interval is five seconds or two minutes.
Another example of a count metric is the number of megabytes of data written to a disk device during a measurement interval. Using the COUNT statistic when querying for a count metric will return the sum of the counts. Count metrics can often be converted into a rate.