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Is there a simple way to tune my Disks?

By on November 20, 2009 in Disk

Absolutely! You can simply follow the instructions on this White Paper: SIMPLIFIED DISK TUNNING

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“Have you ever wondered how to determine the logical disk size looking at Performance Monitor performance metrics?”

By on November 9, 2009 in Disk, NTSMF - Collection Service, Sentry Administration, Windows Performance

It is easy, but requires some calculation. First, look at the logical disk object and add the ‘’% Free Space” and “Free Megabytes” counters to the Perfmon display. Then switch to ‘Report View’. Figure 1. Figure 1. Simply divide Free Megabytes by Free Space (remember this is a percentage, so the displayed value must be […]

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I do not see a drive letter for some of my logical disks. Instead, I see something that looks like HarddiskDmVolumessystemnameDg0Volume1 instead. What is that all about?

By on October 15, 2009 in Disk

Logical disk information containing “HarddiskVolume…” usually indicates an unformatted partition. Knowledge Base article (Q260834) describes the ‘HarddiskVolume’ label as a volume that has been mounted, but not assigned a drive letter. See http://support.microsoft.com/default.aspx?scid=kb;EN-US;q260834 There is another MS KB entry that specfically discusses “HarddiskDmVolumes” names. See http://support.microsoft.com/?kbid=274311. This KB article explains that after you convert a […]

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Why are the Logical Disk counters zero?

By on October 15, 2009 in Disk

This will occur on Windows 2000 if you have never issued the diskperf -yv command to enable the Logical Disk measurements. When diskperf is not active, the corresponding Counters in System Monitor are zero. In Windows 2000, only the Physical Disk counters are enabled by default (this is equivalent to issuing the diskperf -yd command.) […]

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How was the problem with the % Disk Time Counter fixed in Windows 2000?

By on October 15, 2009 in Disk

Maybe not fixed exactly, but ultimately, this problem is addressed quite nicely in Win2K (although it would arguably be better had the older % Disk Time Counters – now obsolete –not been retained). Windows 2000 adds a new Counter to the Logical and Physical Disk Objects called % Idle Time. Disk idle time accumulates in […]

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The Logical/Physical Disk % Disk Time counters look wrong. What gives?

By on October 15, 2009 in Disk

The % Disk Time counters are capped in System Monitor at 100% because it would be confusing to report disk utilization > 100%. This occurs because the % Disk Time counters do not actually measure disk utilization. The Explain text that implies that it does represent disk utilization is very misleading. What the Logical Disk […]

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I am concerned about the overhead of the diskperf measurements. What does this feature cost?

By on September 29, 2009 in Disk

There is very little overhead involved with the collection of diskperf measurements.  We strongly recommend that you enable all disk performance data collection on any system where you care about performance. Even if you don’t care that much about performance, you should turn on Logical Disk reporting at a minimum. The Logical Disk Object contains […]

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I see a value of 2.63 in the Ave Disk Queue Length Counter field. How should I interpret this value?

By on September 29, 2009 in Disk, Performance Metrics, Performance Sentry

The Ave Disk Queue Length Counter is derived from the product of Avg.Disk sec/Transfer) times Disk Transfers/sec, the average response of the device times the I/O rate. This corresponds to a well-known theorem of Queuing Theory called Little’s Law, which states: N = l * Sr where N is the number of outstanding requests in […]

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