From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Building RAID5 w/o a Hot Spare Date: Mon, 01 Feb 2010 16:45:48 -0500 Message-ID: <4B674B8C.9010200@tmr.com> References: <1264603577.1928.4.camel@test.apertos.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1264603577.1928.4.camel@test.apertos.eu> Sender: linux-raid-owner@vger.kernel.org To: =?UTF-8?B?TWljaGHFgiBTYXdpY3o=?= Cc: linux-raid List-Id: linux-raid.ids Micha=C5=82 Sawicz wrote: > Dnia 2010-01-27, =C5=9Bro o godzinie 09:26 -0500, Carlos Williams pis= ze: > =20 >> I am building a Linux system which has 4 identical 'fd' partitions o= n >> each of the 4 drives. I don't want to use the 4th partition or disk = if >> you would like to call it as a 'hot spare'. I would like to span the >> entire array over the 4 drives. My question is does my command look >> correct for doing so? >> =20 > > I'm not sure I understand what you want to achieve. A 'spare' disk is > one that isn't used until any of the other fail, then the spare repla= ces > the failed one. The term 'hot spare' is used to identify a disk that = is > a mirror of one of the other drives, but there's no support for that = in > Linux Software-RAID. > > =20 >> mdadm --create /dev/md0 --level=3D5 --raid-devices=3D4 /dev/sda2 /de= v/sdb2 >> /dev/sdc2 /dev/sdd2=20 >> =20 > > This will create a RAID5 array of 4 devices, yes. Capacity will be 3 = x > sd?2. Failure of any one of those disks will not harm the data. > > =20 A hot spare is in and spinning, or at least powered up, ready to use=20 with software. And software raid does support putting a raid, such as=20 raid-1 or even raid-5, or members which are raid-1 with a write mostly=20 drive and ready to go. --=20 Bill Davidsen "We can't solve today's problems by using the same thinking we used in creating them." - Einstein -- 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