From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: In this partition scheme, grub does not find md information? Date: Tue, 29 Jan 2008 19:46:58 +0300 Message-ID: <479F5882.8050400@msgid.tls.msk.ru> References: <479EAF42.6010604@pobox.com> <18334.46306.611615.493031@notabene.brown> <479F07E1.7060408@pobox.com> <479F0AAB.3090702@rabbit.us> <479F331F.7080902@msgid.tls.msk.ru> <479F3C74.1050605@rabbit.us> <479F42A5.8040007@msgid.tls.msk.ru> <20080129162640.GA16250@rap.rap.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20080129162640.GA16250@rap.rap.dk> Sender: linux-raid-owner@vger.kernel.org To: =?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= Cc: Peter Rabbitson , Moshe Yudkowsky , linux-raid@vger.kernel.org List-Id: linux-raid.ids Keld J=F8rn Simonsen wrote: > On Tue, Jan 29, 2008 at 06:13:41PM +0300, Michael Tokarev wrote: >> Linux raid10 MODULE (which implements that standard raid10 >> LEVEL in full) adds some quite.. unusual extensions to that >> standard raid10 LEVEL. The resulting layout is also called >> raid10 in linux (ie, not giving new names), but it's not that >> raid10 (which is again the same as raid1+0) as commonly known >> in various literature and on the internet. Yet raid10 module >> fully implements STANDARD raid10 LEVEL. >=20 > My understanding is that you can have a linux raid10 of only 2 > drives, while the standard RAID 1+0 requires 4 drives, so this is a h= uge > difference. Ugh. 2-drive raid10 is effectively just a raid1. I.e, mirroring without any striping. (Or, backwards, striping without mirroring). So to say, raid1 is just one particular configuration of raid10 - with only one mirror. Pretty much like with raid5 of 2 disks - it's the same as raid1. > I am not sure what vanilla linux raid10 (near=3D2, far=3D1) > has of properties. I think it can run with only 1 disk, but I think i= t number of copies should be <=3D number of disks, so no. > does not have striping capabilities. It would be nice to have more=20 > info on this, eg in the man page.=20 It's all in there really. See md(4). Maybe it's not that verbose, but it's not a user's guide (as in: a large book), after all. /mjt - 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