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Perfmon disk monitoring

I am trying to understand the difference between the following:

Avg. Disk Bytes/Write - is the average number of bytes transferred to the disk during write operations.

Disk Write Bytes/sec - is rate at which bytes are transferred to the disk during write operations.

When I monitor these 2, I can't see any correlation between them. What is the 'average number of bytes transferred' vs. 'rate at which bytes are transferred'?

Also, I've read that 'Disk Transfers/sec' is an exact measure of IOPS. Is this how to monitor IOPS?

oztrodamus

Hi Blizzard, may I ask what your goal is? Are you having disk performance issues?

B1izzard

ASKER

I'm not having performance issues. I'm just trying to learn what the various counters measure. I noticed the scale is different on both. One is .0001 and the other is .01. The numbers for both seem completely unrelated even though the counters sound like the do virtually the same thing.

oztrodamus

No I don't think they are related in the sense that you are required to use both statistics together. But both are meaningless by themselves. You would want to couple these with other stats to get an overall picture of what is occurring with your I/O sub-structure. I believe "Avg. Disk Bytes/Write" has to do with the averaging of the SIZE of the write operations where as "Disk Write Bytes/sec" has to do with the RATE at which they are being written.

B1izzard

ASKER

I can understand the SIZE, but the RATE is ??? If 250KB passes through at a 1 second interval, the SIZE would be 250KB, but wouldn't the RATE also be 250KB, since it would go through at a RATE of 250KB/sec?

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oztrodamus

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