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

[Warren Block]

On Thu, 16 Sep 2010, Alexander Best wrote:

> On Wed Sep 15 10, Oliver Fromme wrote:
>> Warren Block <wblock at wonkity.com> wrote:
>> > [...]
>> > 8. Alexander Motin has an updated CAM version of the ATA system which
>> > will eventually replace the existing one.  In -CURRENT, anyway.  He was
>> > kind enough to look at my event handler.  My understanding is that he is
>> > looking at implementing the head parking/standby mechanism in that new
>> > code.
>>
>> The patch below will work with the new CAM ATA driver
>> (i.e. ada(4) disks).  It adds a sysctl, so you can switch
>> the spin-down off if you're going to just reboot:
>> # sysctl kern.cam.ada.spindown_shutdown=0
>
> i haven't tested your patch yet, but i don't think deciding whether to spin
> down the hdd should be decided merely from the sysctl value.
>
> the hdd should spindown when a shutdown has been issued and not spindown,
> if a reboot has been issued.

It's been a while, but the problem I found when comparing the NetBSD 
code was that there didn't appear to be a way to tell from within the 
FreeBSD driver whether it was a shutdown or reboot.