From: Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>
To: "Rainer Fügenstein" <rfu@oudeis.org>
Cc: linux-raid@vger.kernel.org
Subject: Re: SATA start unit command?
Date: Mon, 18 Mar 2013 18:32:33 +0100 [thread overview]
Message-ID: <20130318173233.GA2295@lazy.lzy> (raw)
In-Reply-To: <103777438.20130318003050@oudeis.org>
On Mon, Mar 18, 2013 at 12:30:50AM +0100, Rainer Fügenstein wrote:
> hi,
>
> for some reasons I need to keep power consumption at startup as low as
> possible. since the server is booting from SSD, it is possible to send
> a "start unit" (or similar) command to all SATA drives early in the
> init process.
>
> as far as I've searchengined, the drives and the SATA controller need
> to support this feature. but my assumption is that when the drives are
> not needed at startup (since they would be started by the OS), the
> controller won't need to support "start unit". what is your
> experience on this matter?
>
> drives in question are WD Green 3TB drives (WDC WD30EZRX-00DC0B0), the
> controllers at hand are a promise SATA 300 TX4 (don't laugh ;-) ) and
> a supermicro AOC-SAT2-MV8.
Hi Rainer,
I'm facing a similar issue.
That's what I got so far...
Many HDDs, but it seems not all, support the so
called Staggered Spin Up, this means they are in
sleep mode, when powered up.
A SATA bus scan will wake them up.
The Linux AHCI driver performs, per default, but
it could be changed by parameter, a serial bus
scan. This means it will wake up the HDDs one after
the other sequentially and not alltogether.
At least, this is what I understood, but I did not
tested it personally, I just trust the information
I found around.
Check "Linux AHCI SSS" with some search engine and
some patience.
Other drivers I do not know.
If you boot from SSD and you program the HDDs to
stay sleepy (jumper, firmware or cable select,
more info at https://en.wikipedia.org/wiki/Spin-up
and referenced links) it *should* work.
Hope this helps,
bye,
pg
>
> tnx.
>
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next prev parent reply other threads:[~2013-03-18 17:32 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-17 23:30 SATA start unit command? Rainer Fügenstein
2013-03-18 17:32 ` Piergiorgio Sartor [this message]
[not found] ` <CAD9gYJLkpmgSY1_U=1H6b+oJJB_R60cHKqs2NCY4wkRL9xmu5w@mail.gmail.com>
2013-03-19 20:09 ` Re[2]: " Rainer Fügenstein
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