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

[Garrett Cooper]

On Wed, Oct 27, 2010 at 5:41 AM, Alexander Best <arundel at freebsd.org> wrote:
> On Thu Oct 21 10, Alexander Best wrote:
>> On Thu Oct 21 10, Bruce Cran wrote:
>> > On Thu, 21 Oct 2010 14:33:49 +0200
>> > Dag-Erling Smørgrav <des at des.no> wrote:
>> >
>> > > The problem with setting a short idle timeout is that, on a typical
>> > > laptop or desktop system, you end up spinning the disk down and back
>> > > up several hundred times a day, which increases power consumption, I/O
>> > > latency and wear.
>> >
>> > Do we think our users are silly enough to set a short timeout of just a
>> > few minutes?  I'd think most would use a setting of 20-30 minutes at
>> > a minimum. I never did understand why there were so many warnings;
>> > after all, some laptops even come with a default APM scheme in their
>> > HDDs that powers the disk down after 7 seconds!
>>
>> personally i still think something like the attached patch would be nice to
>> have. there's a chance users might type the following:
>>
>> 'atacontrol spindown device 10'
>>
>> thinking the timeout value is measured in minutes. although this gets mentioned
>> in atacontrol(4) it might still be worth reminding the user that he/she is
>> performing actions which could damage the hardware.
>
> i just stumbled upon PR 144770, where a somebody seems to have mistaken the
> spindown value for minutes instead of seconds. so i really think we should have
> this warning in atacontrol!
>
> +1 from brucec, if i understood him correctly.
>
> another possibility would be of course changing the spindown value from seconds
> to minutes. imo this seems very reasonable, because measuring spindown time in
> seconds is too fine grained and not intuitive. just like specifying the
> 'shutdown -p XX' delay in microseconds would not be useful. ;)
>
> cheers.
> alex
>
>>
>> cheers.
>> alex
>>
>> >
>> > --
>> > Bruce Cran
>>
>> --
>> a13x
>
>> diff --git a/sbin/atacontrol/atacontrol.c b/sbin/atacontrol/atacontrol.c
>> index 4354ddf..75a131a 100644
>> --- a/sbin/atacontrol/atacontrol.c
>> +++ b/sbin/atacontrol/atacontrol.c
>> @@ -317,6 +317,10 @@ ata_spindown(int fd, const char *dev, const char *arg)
>>
>>       if (arg != NULL) {
>>               tmo = strtoul(arg, NULL, 0);
>> +             if (tmo < 600)
>> +                     warnx("setting spindown timeout below 10 minutes is \
>> +                           not recommended (see EXAMPLES section of \
>> +                           atacontrol(8))\n");
>>               if (ioctl(fd, IOCATASSPINDOWN, &tmo) < 0)
>>                       err(1, "ioctl(IOCATASSPINDOWN)");
>>       } else {

    Why not just be consistent with other interfaces and provide
suffixes for the values to parse out integral times (i.e. 1 [second],
1m, 2h)? As long as the value is behavior is properly documented in
the manpage (and potentially as examples in the usage message), that
should be enough.
Thanks,
-Garrett