[ltp] hdparm & spindown time : still having problems

[Noah Dain]

On 12/15/05, Paul RIVIER <paul.rivier@eleve.emn.fr> wrote:
>
> >does noflushd spin down your drives?  if so, it should at least
> >provide a workaround.
> >
> >
> YES IT DOES WORK !
> (i apoligize for what I previously said)
>
> But I'd like to undersand why :)
>
> So ... Do you know how noflushd operates ?
> Seems like it  works this way :
> 1) monitor IO stats
> 2) If no IO for a sufficient amount of time, issues a hdparm -y command.
> Basicaly, noflushd could work on a drive on which hdparm -S would not wor=
k,
> but hdparm -y would ... true ?
>
>
> While hdparm -S command write directly in the HDD apm registers.
> Can anyone confirm that ?
>
> Thank you :)
>
>
> Paul
> --

I'm not exactly sure why it works, but a comment in the source of
noflushd states that is uses multiple methods to spin down a drive, as
not all drives obey the same commands.

Just some other things I've run across:

http://www.xs4all.nl/~bsamwel/laptop_mode/

These are more advanced laptop-mode scripts/configs than what ships
with the kernel.  Same author, but avoiding the hassle of changing
things in the kernel distro (read: kernel laptop-mode scripts are
outdated).

I think someone mentioned Ubuntu, so I'll mention that Ubuntu comes
with the old 'laptop-mode' package as an official package.  However,
there is also a port of debian's "laptop-mode-tools" which is the
current set of scripts from the URL above.  However, the
"laptop-mode-tools" package is mutually exclusive with the "noflushd"
package.  I'm not entirely sure why just yet, other than they should
provide a similar service.

Another thing I've seen is that some hard drives don't keep their
settings after they spin down the first time.  They tend to reset
their power settings to default afterwards.  However, this should be
worked around in "laptop-mode-tools".

the short of it is that you cannot rely on all hard drives to manage
their spindown, so something else is needed (noflushd, laptop-mode,
etc).

--
Noah Dain