Hi I have read and read through the internet but still can't find out a decent answer to this question that has been bugging me - what does "perfmon /wmi" actually do that "perfmon" doesn't? I assume it uses WMI, but could someone expand? Without the switch, will WMI 'counter' not be picked up? And what is different between WMI counters and the usual Perfmon ones?

If you use Windows server 2003 or above it doesn't do anything more. But if you use older version of windows server (NT or Windows 2000 server) the program obtains performance data from WMI. So you can see performance counters obtained from WMI. ref: http://technet.microsoft.com/en-us/library/cc778986(WS.10).aspx "When this option is specified, the program obtains performance data by means of Windows Management Instrumentation (WMI) instead of the registry. WMI Hi-Perf providers can then expose performance counters, which in turn appear in System Monitor or are logged by the Performance Logs and Alerts Service. For Windows XP and the Windows Server 2003 family, all WMI counters now appear through the use of a reverse adapter regardless of whether you use the /wmi option."Volkan Sert

When perfmon is ran without the /WMI switch the performance counter information is provided by the HKEY_PERFORMANCE_DATA key in the registry. This key is only accessible programmatically through windows registry functions; you won't find it in the registry. the key itself does not hold the counter information. The registry functions use this key to fetch the counter information from performance data providers. When we do a Perfmon /Wmi, the perfmon information is provided by the wmi performance data providers The information for performance object and counters are stored in certain wmi classes ex: Win32_PerfFormattedData_PerfOS_Memory http://msdn.microsoft.com/en-us/library/aa392740%28VS.85%29.aspx http://msdn.microsoft.com/en-us/library/aa392397%28VS.85%29.aspx#performance_data_providers Madhurjya Bora OS performance Team, MSFT

Thanks, but I'm a little confused :) The article says: "For Windows XP and the Windows Server 2003 family, all WMI counters now appear through the use of a reverse adapter regardless of whether you use the /wmi option." Is that basically saying that the WMI counters appear in Perfmon on 2003 Server and later systems, regardless of whether the /wmi switch is used? In other words, we only need to use the /wmi switch with Windows 2000 Server and prior?

Does anyone know the answer to this?