Summary: Re: Spin down HDD after disk sync or before power off

Alexander Motin mav at FreeBSD.org
Sun Oct 24 17:09:00 UTC 2010


Bruce Cran wrote:
> On Sun, 24 Oct 2010 19:47:57 +0300
> Alexander Motin <mav at FreeBSD.org> wrote:
> 
>> Comparing two ways implementing spindown, I've recalled that both of
>> them using xpt_polled_action() method, which depends on working
>> controller polling operation. So they could be almost equaly not good.
>> But the method present in HEAD now is more universal. Looking on fact
>> that need of spindown is not so obvious for SCSI devices (in SAN
>> environments), we can just make kern.cam.power_down tunable a bitmask
>> of supported protocols for now. Patch is attached.
> 
> I've just committed the patch to move the functionality into ada(4).
> Should it be reverted?

Both solutions are possible. I don't have strong enough position to
hurry now, when it is already done. It would be nice to hear opinion of
SCSI people whether this functionality needed/safe there.

-- 
Alexander Motin


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