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

[Alexander Best]

On Wed Oct 27 10, Garrett Cooper wrote:
> 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.

that would increase usability, since users don't have to specify large values
in seconds, if they e.g. want the spindown to happen after 24 hours (24*60*60).
but this will not solve the real issue: specifying 'atacontrol spindown 1s'
WILL damage your hardware! imo users should be reminded about this even if this
is already mentioned in the manual.

also: will current scripts which set 'atacontrol spindown 600' e.g. continue to
work after implementing the use of suffixes?

> Thanks,
> -Garrett

-- 
a13x