How many IOPS can a single disk provide?
February 15th 2010
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I wish I could retract that comment about adding:- at the point the seek is done, you need to wait for the platter to spin into place, on average half a turn (the latency time). They do therefore happen in sequence! (If it was not for those pesky disks always spinning, I’d have been right!). Lesson learned: don’t let intuition lead you astray, don’t blog in haste, and realise that sometimes oft repeated advice is true. I am keeping the post up out of intellectual honesty, but will be blogging furiously to get it off the front page.
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I have just read an article on roughly how many IOPs you can expect from a single disk and encountered what I consider to be a frequently repeated mistake in the calculation.
Before I begin I want to point out that it is only an approximation anyway and caching in enterprise storage systems makes it perhaps a moot point anyway.
The article is here if you want to go and see it.
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