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See the answers to these posts. It appears to be the result of how it's calculated.
Strange % Disk Read Time counter reading
Mikhail Firsov
1,881
Reputation points
Hello!
While monitoring my new server(2019) I was puzzled by the following fact: when I'm coping files from my "standalone" hard drive( logival disk E:_ - the drive connected to the mothebords' SATA controller - not a raid member, to the logical drive (D:) which is the RAID1 volume I see this:
As far as I know the % (either read or write) can not be > 100 for a single drive - how in this case E: shows 172% ???
Thank you in advance,
Michael
Windows for business Windows Server Devices and deployment Set up, install, or upgrade
Windows for business Windows Server User experience Other
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Mikhail Firsov 1,881 Reputation points
2021-02-09T14:42:57.433+00:00 Seems the overlapping can happen only with RAID-ed disks:
"If you have multiple disks in a Raid arrangement, the overlapped input/output happens because the OS can read and write to multiple disks, and this could show value that are higher than 100 percent for this counter." - but my volume E: is the single hdd! :(
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MotoX80 36,291 Reputation points2021-02-09T16:03:02.187+00:00 The % Disk Read Time and % Disk Write Time counters can exaggerate disk time. This is because they report busy time based on the duration of the I/O request, which includes time spent in activities other than reading to or writing from the disk. It then sums up all busy time for all requests and divides it by the elapsed time of the sample interval. If multiple requests are in process at a time, the total request time is greater than the time of the sample interval; as a result, reported disk utilization can exceed actual utilization.
I have a Win10 laptop with a single HDD. Running chkdsk with a perfmon interval at 10 seconds shows this below. The disk queue length counters might be better to watch to see if your drive is overloaded.
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Mikhail Firsov 1,881 Reputation points
2021-02-10T08:14:11.64+00:00 I thought this "The % Disk Read Time and % Disk Write Time counters can exaggerate disk time. ..." this does not apply to my server as this article is about VM, not a physical machine. 346% on a single drive... no comments - it means this counter is completely useless.
Thank you for the help!
Regards,
Michael