Date: Fri, 05 Mar 2010 13:18:03 +0100 From: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> To: Alexander Motin <mav@FreeBSD.org> Cc: FreeBSD-Current <freebsd-current@freebsd.org>, "James R. Van Artsdalen" <james-freebsd-current@jrv.org> Subject: Re: Pack of CAM improvements Message-ID: <86hbov3qtg.fsf@ds4.des.no> In-Reply-To: <4B69817B.8090706@FreeBSD.org> (Alexander Motin's message of "Wed, 03 Feb 2010 16:00:27 %2B0200") References: <4B55D9D4.1000008@FreeBSD.org> <823F6536-32A7-4BC6-9C6A-C84865A38458@samsco.org> <4B570B4C.9000203@jrv.org> <4B69817B.8090706@FreeBSD.org>
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Alexander Motin <mav@FreeBSD.org> writes: > I've just added Power Up In Stand-by (PUIS) feature support into CAM > ATA in HEAD. It is one of the ways to implement staggered spin-up for > ATA devices. Now CAM will spin-up no more then 4 of such devices at a > time. Hmm, how does that work? Doesn't the BIOS spin the disks up long before the kernel even loads? Can you set a flag on the disk to tell it not to? This is a very real issue for me. I have a file server that can't cold boot because the disks take too long to spin up and / or the PSU can't deliver enough power to spin them all up at the same time. I would love to be able to delay spinning up each disk until it's actually needed (i.e. /etc/rc.d/zfs start). DES --=20 Dag-Erling Sm=C3=B8rgrav - des@des.no
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