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

[Tijl Coosemans]

On Thursday 16 September 2010 16:10:22 Oliver Fromme wrote:
> Tijl Coosemans wrote:
>> I would just spin down the disk in case of a halt. An unwanted spin
>> down is harmless compared to an emergency shutdown and usually the
>> intention is to power off rather than reboot.
> 
> Is it?  When I intend to power-off, I use shutdown -p, not
> shutdown -h.  Quite often (but not always) when I halt a
> machine, I'm going to reboot to multi-user, not power off.

Hmm, I suppose support for power off is ubiquitous nowadays. It used to
be that halt meant: bring the system in a state where we can safely cut
the power. In that case it makes sense to let halt spin down the disks.
If you intend to reboot why not explicitly reboot rather than halt?
Also, to go from single to multi user mode you can just exit(1) the
shell.

> In that case I certainly wouldn't want to spin the drives
> down and have them spun up immediately afterwards.  I don't
> think that wear&tear caused by that procedure is completely
> insignificant (although it's certainly less of a problem
> than emergency unloads).
> 
> For that reason I definitely want to have a way to disable
> the spindown function manually.

Ok, I'm soft on the sysctl really, it wouldn't hurt anyone. Although,
if the intention is to just override the default behaviour at the time
of shutdown you might as well just add an option to halt(8). A "don't
spin down disks" option would fit in with the other options there.
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