Linux RAID subsystem development
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From: Roman Mamedov <rm@romanrm.ru>
To: Phillip Susi <psusi@cfl.rr.com>
Cc: Piergiorgio Sartor <piergiorgio.sartor@nexgo.de>,
	Roberto Spadim <roberto@spadim.com.br>,
	linux-raid@vger.kernel.org
Subject: Re: RAID HDDs spin up sequence
Date: Tue, 1 Feb 2011 17:39:32 +0500	[thread overview]
Message-ID: <20110201173932.2455a20f@natsu> (raw)
In-Reply-To: <4D4765B2.7090002@cfl.rr.com>

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On Mon, 31 Jan 2011 20:45:22 -0500
Phillip Susi <psusi@cfl.rr.com> wrote:

> If you want to force serial wakeup, you would need to do some hacking in 
> libata or the scsi layer to only allow one wakeup request at once.  Of 
> course, with a 6 disk raid where each disk takes 6 seconds to spin up, 
> you will be waiting 36 seconds to get your data.  Not exactly desirable.

Well, if the other option is to have your system hard-reset because the PSU
overloads from 12-20-24 disks spinning up at once (you know staggered spin-up
is supported by disks/controllers for a reason), then the wait does not look so
bad.

My take on the problem: just don't spin down your RAIDs.

-- 
With respect,
Roman

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  reply	other threads:[~2011-02-01 12:39 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-31 20:18 RAID HDDs spin up sequence Piergiorgio Sartor
2011-01-31 21:09 ` Roberto Spadim
2011-01-31 21:10   ` Roberto Spadim
2011-01-31 21:11   ` Mathias Burén
2011-01-31 21:25     ` Roberto Spadim
2011-01-31 21:29       ` Mathias Burén
2011-01-31 21:35         ` Roberto Spadim
2011-01-31 22:23   ` Piergiorgio Sartor
2011-01-31 22:42     ` Roberto Spadim
2011-01-31 22:42       ` Roberto Spadim
2011-01-31 23:07       ` Piergiorgio Sartor
2011-01-31 23:12         ` Roberto Spadim
2011-02-01  1:45         ` Phillip Susi
2011-02-01 12:39           ` Roman Mamedov [this message]
2011-02-01 13:10           ` John Robinson
2011-02-01 21:37             ` Stan Hoeppner
2011-02-01 22:46               ` Roberto Spadim
2011-02-01 13:55     ` brian.foster
2011-02-01 14:37       ` Roberto Spadim
2011-02-01 14:44         ` Roberto Spadim
2011-02-01 15:01           ` John Robinson
2011-02-01 15:46             ` Roberto Spadim

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