Have a look at this:
root@cisd-ruapehu # time dd if=/dev/zero of=80G bs=8192k count=10000 10000+0 records in 10000+0 records out real 2m41.484s user 0m0.064s sys 2m26.890s
Quick calculation. This is a 44 disk raidz2 striped in the “optimal” manner according to the guide quoted. This is roughly 80GB in 161 seconds. Or, 0.497 GB/s. Under 500 GB/s. Yup.
They show off their blazing 560 MB/s performance on smaller (mostly cached 16GB system ram 20GB file) files.
Now I have independent confirmation of how much faster our 16 bay 3U JackRabbit is than this, as well as our 24 bay 4U unit. Don’t even need to get to the 48 bay 5U unit.
Took a snapshot (pdf) just in case this goes into a memory hole.
Our 3U unit sports about 750+ MB/s on the same test at well under 1/2 the price. Our 24 bay 3U unit sustains 1.6 GB/s on the same test with about the same capacity, at under 1/2 the list price of this unit.
We could put 10k or 15k RPM SAS drives in JackRabbit, but that would be just plain old cruel of us.
Part of the reason I bring any of this up is that we often get the “2GB/s” number thrown at us in discussions. Customers know about this number. We ask them (practically beg them) to test it. We often hear … well … rather different numbers back. Sadly, we can’t use any of them as they aren’t in the public domain. These numbers are though, and hopefully they won’t go down the memory hole.
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