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I ran IOmeter on a Windows Server 2008 R2 SP1 server for 18 hours and when I clicked on "Stop current Test and Save Results" it stopped the worker processes (I only had 1).

When looking at the results in the csv file it hardly shows shows size of blocks (512, 4096 etc) and % of read etc but when looking at the Results section it shows some data from when I started IOMeter and stats of when I stopped it but nothing inbetween?

The file size of the csv is 8kb but the file size of iobw.tst is 31GB! I have a feeling all the data is being stored in iobw.tst rather then the results file.

I assume I messed up some setting somewhere or something or is this normal? I don't remember changing any of the default setting except for the view of where I selected "Last Update" instead of "Start of Test"

Any ideas?

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up vote 3 down vote accepted

Iometer probably hadn't actually done anything yet. It was probably still preparing the drive, hence the 31GB iobw.tst file. Unless configured otherwise, Iometer prepares a test file the size of the drive being tested. You'll need to set the maximum disk size to prevent it from doing that. There are a number of Iometer tutorials available, this is juist one -

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thanks - I did read some tutorials but your one was more comprehensive. It was preparing the drive and had got stuck as it turns out. I am running it again now and seems fine. Thanks again. – lara400 Feb 7 '14 at 16:17
Glad to help... – joeqwerty Feb 7 '14 at 16:36

I think you'd do well to read-up on how to use IOmeter. There are a lot of tutorial sites and videos out there for the searching. You should also read the IOmeter user's guide if you haven't already.

The "iobw.tst" file is the file used to host reads / writes, not the results. It will be large.

The "results.csv" file will be small, because only summary information from the run is reported. The columns in the file are fairly self-explanatory.

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