From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keld =?iso-8859-1?Q?J=F8rn?= Simonsen Subject: Re: A few remaining questions about installing to RAID-10 Date: Fri, 2 Oct 2009 17:06:41 +0200 Message-ID: <20091002150641.GB4342@rap.rap.dk> References: <887103.5263.qm@web38801.mail.mud.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Ben DJ Cc: chimera_god@yahoo.com, robin@robinhill.me.uk, linux-raid@vger.kernel.org List-Id: linux-raid.ids On Fri, Oct 02, 2009 at 07:54:04AM -0700, Ben DJ wrote: > Hi everybody, >=20 > 2009/10/2 Keld J=F8rn Simonsen : > > You can boot from a raid-10,n2 with the superblock last, standard > > raid10,n2 will do. But the normal thing is to boot from raid-1 > > > > There is a description of a setup at > > http://linux-raid.osdl.org/index.php/Preventing_against_a_failing_d= isk >=20 > Thanks for the URL. Is there a reason that raid-1 is the "normal > thing"? Just popularity or something technical? it is because raid1 is what traditionally worked. raid10,n2 will not wo= rk in some situations. raid10 is "new" and "dangerous" (FUD). Many people do not know about raid10, and its wonders. > In your reference it says "The root file system can be on another rai= d > than the /boot partition. We recommend an raid10,f2, as the root file > system will mostly be reads, and the raid10,f2 raid type is the > fastest for reads, while also sufficiently fast for writes. Other > relevant raid types would be raid10,o2 or raid1." and "a small /boot > partition. We recommend something like 200 MB on an ext3 raid1". >=20 > How or why did you arrive at "raid-10,n2 with the superblock last"? what lilo and grub really do is that they just read from one disk, so i= f the raid type happens to be the same layout as a non-raid partition, i= t works. raid10,n2 default layout (ver 0.90) is equivalent with non-raid, as the raid superblock is in the end of the partition. I understand tha= t other versions of the superblock are put other places, such as in the beginning of the partition. best regards keld -- 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