On Fri, Sep 11, 2009 at 3:20 PM, Eric D. Mudama <edmud...@bounceswoosh.org>wrote:
> On Fri, Sep 11 at 13:14, Tim Cook wrote: > >> Better IOPS? Do you have some numbers to back that claim up? I've never >> heard of anyone getting "much better" IOPS out of a drive by simply >> changing the interface from SATA to SAS. Or SATA to FATA for that >> matter. A 7200RPM drive is limited by the 7200RPM's, not the interface >> it's attached to. >> > > Depends on the model of drive. > > A number of vendors put relatively larger magnets and stronger > actuators in their enterprise designs, where the customers are willing > to pay for it. This can significantly decrease track-to-track seek > times, which improves IOPS. > > On top of that, many enterprise drives are using smaller platters > and/or higher RPM, both of which also help IOPS at shallow queue > depths. > > At infinitely high queue depth, IOPS basically becomes a function of > how quickly the servo system can settle, since seek distances approach > zero (both linearly and rotationally) as the number of operations to > choose from goes to infinity. > > The question wasn't about consumer vs. enterprise drives. He said the SAS interface improves IOPS. Please don't change the topic of discussion mid-thread. --Tim
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