Microsoft KB Archive/102020

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Article ID: 102020

Article Last Modified on 11/1/2006


  • Microsoft Windows NT Advanced Server 3.1
  • Microsoft Windows NT Workstation 3.1
  • Microsoft Windows NT Advanced Server 3.1
  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Server 4.0 Standard Edition

This article was previously published under Q102020


Disk performance counters, the Diskperf service, must be started prior to the Performance Monitor in order to monitor disk performance. Disk performance counters are disabled by default.


The impact of the Performance Monitor on the overall performance of a system is minimal. However, the counters (which are necessary to monitor disk performance) will have a slight impact to the overall system performance. For this reason, these counters are not started by default. Therefore, for best system performance, they should be started prior to beginning disk performance monitoring and then terminated.

To enable the Diskperf service, use either of the following two procedures.

Procedure 1

  1. Choose the Command Prompt icon in the Main group.
  2. At the command prompt, type "DISKPERF -Y" (without the quotation marks) and press ENTER. You will receive the following message:

    Disk performance counters on this system are now set to start at boot. This change will take effect after the system is rebooted.

Procedure 2

  1. Start Control Panel, choose Devices and change the startup value of Diskperf to Boot.
  2. Restart your computer.

Once the system is restarted, disk performance monitoring is enabled. After monitoring disk performance, you should turn off the Diskperf service.

Use to following command to disable the Diskperf service:

DISKPERF -N -- This will set the disk performance counters to never start. For best overall system performance issue this command from the command prompt after completing disk performance monitoring.

Other helpful commands that may be issued from the command prompt to assist in disk performance monitoring are:

DISKPERF /? -- Displays help for the DISKPERF command.

DISKPERF -- Displays the current status of the disk performance counters along with help for the DISKPERF command.

Diskperf -YE, the E allows monitoring of all NT Software Fault Tolerant sets that utilize the FTDISK device driver. This does not apply to hardware arrays.

Additional query words: prodnt physicaldisk physical disk object counter zero

Keywords: kbenv KB102020