[snip] There are three factors that affect how fast you can get to the next sector:
seek time settle time rotational latency
Most drives only list the first, and don't bother to mention the other two.
Ah yes, one of my (very) few still functioning brain cells was nagging about another bit of time in the equation :)
On many modern drives, the seek times are around 5 to 10 milliseconds. [snip]
Going back to the OPs posting about random_page_cost, imagine I have 2 servers identical in every way except the disk drive. Server A has a 10K rpm drive and server B has a 15K rpm drive. Seek/settle times aren't spectacularly different between the 2 drives. I'm wondering if drive B might actually merit a _higher_ random_page_cost than drive A as, once it gets settled on a disk track, it can suck the data off a lot faster. opinions/experiences anyone?
--
Paul Thomas
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