You can compare actual usage with available resources to determine if a resource shortage is imminent. To monitor SMTP capacity, review both the physical resources of your Exchange server and SMTP service capacity. A physical resource reaches capacity when it is busy 100 percent of the time. A service reaches capacity when requests for service start experiencing delays.
Note To monitor physical capacity, the diskperf utility must be turned on. To activate diskperf, type diskperf -y at a command prompt on the server you want to monitor. You will then need to restart the computer.
The objects to monitor and the counters to use are described in the following table:
|Logical Disk||%Disk Time||Percentage of elapsed time that the selected disk drive is busy servicing read or write requests. A normal reading is less than 70%. If readings continuously rise above 70%, consider adding another Exchange server for SMTP.|
|System||% Registry Quota In Use||The percentage of the Total Registry Quota Allowed that is currently being used by the system. Note that this percentage is not an average, so be sure to check this level a number of times under varying network circumstances.|
|Memory||Available Bytes||Displays the size of the virtual memory currently on the Zeroed, Free, and Standby lists. Zeroed and Free memory is ready for use, with Zeroed memory cleared to zeros. Standby memory is memory removed from a process Working Set but still available. Notice that this is an instantaneous count, not an average over the time interval. A normal reading is greater than 10% of the total memory.|