From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Majed B." Subject: Re: Array Power Management Date: Mon, 7 Sep 2009 12:57:33 +0300 Message-ID: <70ed7c3e0909070257y4bec456h6de9cc6d2981c8ce@mail.gmail.com> References: <292245.77763.qm@web55804.mail.re3.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <292245.77763.qm@web55804.mail.re3.yahoo.com> Sender: linux-raid-owner@vger.kernel.org To: jahammonds prost Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids If you're going to spin down the disks, you'd need to unmount the array first to ensure your data is fine, and after a spin-up then you mount the array again. I would suggest you buy a meter to measure how much power your storage is consuming before you decide on your next action. Personally, I'd turn off the machine altogether if it's not needed during working hours (assuming no one accesses through VPN). Check the BIOS, it may have the capability to wake up the machine on a certain date & time (So you can specify to turn itself on daily @ 8 AM). If not, you should have Wake-up On LAN support, so if you turn off the machine, another machine (a monitoring server) can turn it on for you (just put the wake-up on LAN command as a cron job to execute daily -- perhaps exclude holidays). On Mon, Sep 7, 2009 at 6:48 AM, jahammonds prost wr= ote: > I've been becoming interested in the power consumption of the arrays = I have on a couple of servers here that are basically used as media ser= vers. Since they're not being used when I'm at work, I was looking at t= he possibility of spinning the disks down during certain times, and hav= ing them either spin up at a set time, or (ideally), when there is disk= activity. > > I can do this on single drives using hdparm -S to set the spindown ti= meout, and the disks will spin up on activity as needed. Is there somet= hing similar I can do with an md array? I can see there's a /sys/block/= md0/power/wakeup file, but I can't seem to find any documentation on it= =2E I have thought about doing an hdparm -S on the array disks, but I s= uspect that would be A Bad Thing (tm). > > Does anyone have any advice/pointers? The servers are currently runni= ng fc9 - I'd like them to be Centos, but had to go with fc9, as I=C2=A0= needed Port Multiplier support. > > > Graham > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht= ml > --=20 Majed B. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html