If you're shopping for an SSD, you've surely seen one of those screenshots from CrystalDiskMark with a few green squares, and the 2x4 matrix with results of doing read/write tests for the given hardware:

However, I've never seen anything similar for UNIX — at most what you get is a dd for sequential read/write tests, which gives no indication on the IOPS parameters of the hardware in question.

Is there anything similar to CrystalDiskMark for UNIX to perform various read/write tests like 4KiB Q8T8 etc?

I searched and found the following items in OpenBSD ports, but they seem rather stale (to say the least — randread is still hosted on SourceForge in 2020 and BYTE magazine has reportedly ceased online publication in 2013), and none of these tools make any mention of evaluating modern SSD performance, for which you probably have to have some sort of extra code to deal with the IO queues and threads or whatnot:


1 Answer 1


I think you have missed some of the more common tools in your search.

For some testing I find IOrate(port) nice.

Previously bonnie++ was very common. Still a favourite for testing disks but see Can I determine IOPS on a disk array using bonnie++?.

Today I would say that iozone(port) is mostly used. And it helps you with IOPS

See How to properly test SSD performance for a discussion of the importance of testing with 2x physical RAM with iozone.

I have not used it but fio(port) is a popular choice as well.

And FreeBSD Benchmark Advice is required reading!

None of these are however as simple to use as CrystalDiskMark. You need an understanding of the different caching layers, filesystems etc.

A quick comparison from 2018 can be found at Comparing IO benchmarks: FIO, IOZONE and BONNIE++:

The above is FreeBSD centric but they are readily available for:


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