From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1RBuTU-000467-SD for garchives@archives.gentoo.org; Thu, 06 Oct 2011 20:23:26 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 7E90121C25C; Thu, 6 Oct 2011 20:23:03 +0000 (UTC) Received: from mail-qw0-f53.google.com (mail-qw0-f53.google.com [209.85.216.53]) by pigeon.gentoo.org (Postfix) with ESMTP id B1C8E21C245 for ; Thu, 6 Oct 2011 20:21:11 +0000 (UTC) Received: by qafi31 with SMTP id i31so4526126qaf.40 for ; Thu, 06 Oct 2011 13:21:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=lrXi135Pje+9mP+9fHNQceNcbR+eZQi8KEV3zcqDus8=; b=pZpJSNeqLSmpK3tDvYtq+IkqF2LNJ0M/XZB0gdsQMWf+k7BfflzIWh9IJjtumtimv1 f1CtDDBavxsMpcY0UD3NcJIlfzd9Ip0I84XQ7W5wA6durmbpJw+DXa1g5WJcUWPFZCPb d/08euH2d/es5y7i7ugNLz9rZYPNlvC4xWsNM= Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.224.178.67 with SMTP id bl3mr818572qab.235.1317932471228; Thu, 06 Oct 2011 13:21:11 -0700 (PDT) Received: by 10.224.80.209 with HTTP; Thu, 6 Oct 2011 13:21:10 -0700 (PDT) In-Reply-To: References: <4E8DFE1B.6060403@gmail.com> Date: Thu, 6 Oct 2011 13:21:10 -0700 Message-ID: Subject: Re: [gentoo-user] How can I power disk off? From: Mark Knecht To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: X-Archives-Hash: 6ec0cbe9d54c5bdb175ba835ca0d6c6e On Thu, Oct 6, 2011 at 1:03 PM, Paul Hartman wrote: > On Thu, Oct 6, 2011 at 2:44 PM, Mark Knecht wrote: >> Paul, >> =C2=A0 Would hdparm be advisable if the drive was part of a RAID? I susp= ect not. >> >> =C2=A0 I don't think this applies to the OP but for the sake of discussi= on >> why not include RAID as part of the solution, if possible. > > I use hdparm to set power-saving on all members of my RAID5 and it > works (in my case, I'm setting them to never spin-down). I created a > file /etc/local.d/hd-power-level-fix.start containing one line: > > hdparm -B 254 /dev/sd[abcdef] > > which automatically sets those drives to never spin down. > > In my original recommendation, I hadn't considered hdparm's "spindown > immediately" option. I was thinking of the -B command like I used > above, to adjust the "spin down after X idle time" option. If all > members of the RAID have the same idle time they'll probably all spin > up and down together under normal usage (well, depending what kind of > RAID it is, I suppose). In my case, I found the "click, whirr, click, > whirr, click, whirr, click, whirr, click, whirr" waiting for 5 disks > to spin-up when I accessed the RAID annoying, so I disabled it. (I > have not done any power-consumption measurements to see what that's > costing me...) > My worry was that if the mdraid daemon saw one drive gone - either when starting to spin down or when one spins up slowly - and if mdraid didn't understand that all this stuff was taking place intentionally then it might mark that drive as having failed. I can see the utility of spinning down a RAID in something like a home video server where I keep movies. The machine could be on, ready to serve a movie, but the drives aren't drawing much power. I suspect that there's a pretty substantial power savings on a big RAID if done right, but I haven't done any measurements either. Cheers, Mark