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.
--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com www.2ndQuadrant.us
