From owner-freebsd-current@FreeBSD.ORG  Mon Mar 16 20:03:01 2009
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To: Andriy Gapon <avg@icyb.net.ua>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
In-Reply-To: Your message of "Mon, 16 Mar 2009 18:20:42 +0200."
	<49BE7C5A.2080103@icyb.net.ua> 
Date: Mon, 16 Mar 2009 20:02:58 +0000
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Sender: phk@critter.freebsd.dk
Cc: freebsd-current@freebsd.org
Subject: Re: ata: printf on every spinup/spindown? 
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In message <49BE7C5A.2080103@icyb.net.ua>, Andriy Gapon writes:

>I am playing with ata spindown feature and I think that it is really unnecessary
>to print a message each time ata driver is going to spindown a disk or let it be
>spinned up:
>ad6: Idle, spin down
>ad6: request while spun down, starting.
>ad6: drive spun down.
>ad6: Idle, spin down
>ad6: request while spun down, starting.

The reason I added the printf was to make it very annoying.

Spinning a disk up and down too often wears it out much faster than leaving
it running.

In general you do not want to spin a disk down unless it is going to stay
spun down for at least 15-30 minutes.

If dmesg is going to spin your disk up, then it will wake up every 5 minutes
due to the atrun message and you are clearly doing it wrong.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.