Re: Loud "pop" coming from hard drive on reboot

[Robert Hancock]

Tejun Heo wrote:
> This really isn't a regression.  It's been always like that with libata.
>  libata doesn't make devices go into standby mode and shutdown(8) does
> it for libata.  The problem here is that libata does issue
> SYNCHRONIZE_CACHE on shutdown.  So, the sequence of event is...
>
> 1. shutdown(8) issues SYNCHRONIZE_CACHE followed by STANDBY_NOW

This part is presumably distribution dependent. I have never seen Fedora 
or CentOS shut down drives on power down from the shutdown script/utility..

> 2. kernel shutdown starts
> 3. libata shutdown issues SYNCHRONIZE_CACHE
> 4. power goes off
>
> Some drives seem to spin up at step #3 even when its cache is clean and
> power goes off right after the disk finishes the command.  So, it's
> really bad when it happens - spin down, spin up followed by immediate
> power off.

--
Robert Hancock      Saskatoon, SK, Canada
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Home Page: http://www.roberthancock.com/

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