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IOZone output data must be (egregiously) wrong. (output data attached)

TrumanHW

Member
Joined
Apr 17, 2018
Messages
88
IOzone is reporting that my consumer NVMe SSD drive's performance was:
  • Random 4 KB Reads @ 800,000 IOPS ..!
  • Reads at 16 GB/s ...

IF the units-of-measure ... was wrong ... as in, not KB but Kb, or Bytes, ... even then, the numbers are nutty.
  • Recalculating the units (instead of KB) as bytes, then, instead of 16 GB/s it gets 16 MB/s !?
  • Recalculating the units (instead of KB) as Kbits, then, instead of 16 GB/s it gets 2 GB/s - of mixed 16KB RANDOM reads..??
The output data explicitly says kBytes.


1. IOzone condensed.png

TO SEE THIS SCREEN SHOT UN-EDITED ... DOWNLOAD THE FILE: IOzone condensed.png




The results of this highly-respected & oft-recommended utility are confusing & contradicted by other benchmarking tools.
If I'm correct, I hope it helps others (or alerts the mfr to fix the issue, If inaccurate) ... If I'm wrong, please explain what I missed.
Suggestions (or corrections) anyone...?

XLS attached files includes a screenshot of the CLI output ... but removed (in the the 'Random RW + CLI file) all but random RW info...
XLS attached named "output - IOZone.xls" is the original (unedited) output -- which I cross referenced to the CLI data to confirm it's the same.
 

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Last edited:

cobrakiller58

Senior Member
Joined
Jan 18, 2017
Messages
383
My only thought is this line from the FreeNAS manual.

"Starting with version 9.2.1, FreeNAS® enables compression on newly created ZFS pools by default. Since IOzone creates test data that is compressible, this can skew test results. To configure IOzone to generate incompressible test data, include the options -+w 1 -+y 1 -+C 1 "
 
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