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On Tue, Jun 06 2006, Tejun Heo wrote: > Hi, Jens. > > Jens Axboe wrote: > >On Wed, May 31 2006, Robert Hancock wrote: > >>Bill Davidsen wrote: > >>>The trade-off is that if I have a 15k rpm SCSI drive, it would take a > >>>lot of design changes to make it spin up quickly, and improve a function > >>>which is usually done on a server once every MTBF when replacing the > >>>failed unit. > >>> > >>>I think the majority of very large or very fast drives are in systems > >>>which don't (deliberately) power cycles often, in rooms where heat is an > >>>issue. And to spin up quickly take a larger power supply... 30 sec is > >>>fine with most users. > >>> > >>>Couldn't find a spin-up time for the new Seagate 750GB drive, but the > >>>seek sure is fast! > >>I wouldn't guess that even a 15K drive would take nearly that long. For > >>boot time on servers it doesn't matter much though, disk spinup time is > > > >I do use a 15K rpm drive in my workstation (hello git!), and the spin up > >really isn't that bad. Less than 10 seconds for the actual spin up, I > >would say. > > Can you measure spin up time for your 15k's? Some controllers can't > catch the first D2H FIS after POR and have to wait unconditionally for > spin up for hotplug & resuming from suspend. Currently 8 sec wait is > used but it seems insufficient for your drives. Failing to spinup in > that 8 secs would probably result in timeout of the first reset attempt > and retrial - which currently takes > 30 secs. > > Spin-up time can be measured by first issuing STANDBY and then time how > long IDLE IMMEDIATE takes, I think. The 15K RPM is a SCSI drive, I haven't seen any SATA 15K rpm drives yet. I have the same model in another box, I can measure spinup with START_STOP unit there. I will do so later today, when I fire it up, if you still want to know? -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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