Ivan Voras wrote:
(or if you are looking at raw numbers: a 15,000 RPM drive will sustain 15000/60=250 random IOs per second (IOPS)
That's only taking into account the rotation speed--a 15K drive can do 250 physical commits per second if you never seek anywhere. A true IOPS number also considers average seek latency. A decent 15K drive will be around 4ms there, which makes for 167 IOPS total.
Random note: this discussion is on the wrong list. There are more people interested in this topic who post regularly on pgsql-performance than pgsql-general.
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