From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Subject: Re: raid10,f2 Add a Controller: Which drives to move? Date: Tue, 13 Apr 2010 23:09:26 +1000 Message-ID: <20100413230926.1273fc64@notabene.brown> References: <4BC29670.6020504@unart.cz> <4BC2B887.6020403@stud.tu-ilmenau.de> <4BC2CF14.9000209@unart.cz> <20100413092354.GA7581@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20100413092354.GA7581@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: Keld Simonsen Cc: Simon Matthews , =?UTF-8?B?VG9tw6HFoSBE?= =?UTF-8?B?dWzDrWs=?= , st0ff@npl.de, Linux RAID List-Id: linux-raid.ids On Tue, 13 Apr 2010 11:23:54 +0200 Keld Simonsen wrote: > I am not sure it has been said, but for a 4 disk raid10,f2 array > you should place the first and the second disk on one controller, and= then the 3rd > and 4th on the second controller. Then you would have a copy of all b= locks even > if one controller fails. Uhmm... no. Disk: 1 2 3 4 blocks a b c d e f g h ......... d a b c h e f g If you only have first and second, then block c is missing. You want 1st and 3rd on one controller, 2nd and 4th on the other Then either controller can access all blocks. >=20 > I believe the order is defined by the order the disks are specified i= n > on the mdadm --create line. Correct. NeilBrown >=20 > best regards > keld >=20 > On Mon, Apr 12, 2010 at 08:26:55PM -0700, Simon Matthews wrote: > > 2010/4/12 Tom=C3=A1=C5=A1 Dul=C3=ADk : > > > Stefan /*St0fF*/ H=C3=BCbner napsal(a): > > >> > > >> I cannot quite understand your problem. =C2=A0As every part of t= he array > > >> contains it's own metadata, it doesn't matter to md which /dev/s= dX a > > >> drive is. =C2=A0It might matter a bit for boot-time assembly, bu= t actually > > >> that's what UUIDs are for. > > >> > > > > > > I know how UUIDs work. > > > My problem with device names is not a "critical", it's about "use= r > > > friendliness" of the physical disk management. > > > If a disk fails and I receive email "A Fail event had been detect= ed on md > > > device /dev/md2. It could be related to component device /dev/sdd= 3", how > > > will I know which disk should be replaced, if the device name is = not > > > fixed/persistent? I > >=20 > > Record the serial number of the disks and which bay they are in. > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-rai= d" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > 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 http://vger.kernel.org/majordomo-info.html -- 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