Be careful when testing ZFS with ozone, I ran a bunch of stats many
years ago that produced results that did not pass a basic sanity check. There
was *something* about the ozone test data that ZFS either did not like or liked
very much, depending on the specific test.
I eventually wrote my own very crude tool to test exactly what our
workload was and started getting results that matched the reality we saw.
On Jul 17, 2012, at 4:18 PM, Bob Friesenhahn <bfrie...@simple.dallas.tx.us>
wrote:
> On Tue, 17 Jul 2012, Michael Hase wrote:
>
>> To work around these caching effects just use a file > 2 times the size of
>> ram, iostat then shows the numbers really coming from disk. I always test
>> like this. a re-read rate of 8.2 GB/s is really just memory bandwidth, but
>> quite impressive ;-)
>
> Ok, the iozone benchmark finally completed. The results do suggest that
> reading from mirrors substantially improves the throughput. This is
> interesting since the results differ (better than) from my 'virgin mount'
> test approach:
>
> Command line used: iozone -a -i 0 -i 1 -y 64 -q 512 -n 8G -g 256G
>
> KB reclen write rewrite read reread
> 8388608 64 572933 1008668 6945355 7509762
> 8388608 128 2753805 2388803 6482464 7041942
> 8388608 256 2508358 2331419 2969764 3045430
> 8388608 512 2407497 2131829 3021579 3086763
> 16777216 64 671365 879080 6323844 6608806
> 16777216 128 1279401 2286287 6409733 6739226
> 16777216 256 2382223 2211097 2957624 3021704
> 16777216 512 2237742 2179611 3048039 3085978
> 33554432 64 933712 699966 6418428 6604694
> 33554432 128 459896 431640 6443848 6546043
> 33554432 256 444490 430989 2997615 3026246
> 33554432 512 427158 430891 3042620 3100287
> 67108864 64 426720 427167 6628750 6738623
> 67108864 128 419328 422581 6666153 6743711
> 67108864 256 419441 419129 3044352 3056615
> 67108864 512 431053 417203 3090652 3112296
> 134217728 64 417668 55434 759351 760994
> 134217728 128 409383 400433 759161 765120
> 134217728 256 408193 405868 763892 766184
> 134217728 512 408114 403473 761683 766615
> 268435456 64 418910 55239 768042 768498
> 268435456 128 408990 399732 763279 766882
> 268435456 256 413919 399386 760800 764468
> 268435456 512 410246 403019 766627 768739
>
> Bob
> --
> Bob Friesenhahn
> bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
> GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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--
Paul Kraus
Deputy Technical Director, LoneStarCon 3
Sound Coordinator, Schenectady Light Opera Company
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