From owner-freebsd-geom@FreeBSD.ORG Thu Dec 14 23:05:50 2006 Return-Path: X-Original-To: freebsd-geom@freebsd.org Delivered-To: freebsd-geom@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D9D1A16A4B3 for ; Thu, 14 Dec 2006 23:05:50 +0000 (UTC) (envelope-from lulf@stud.ntnu.no) Received: from merke.itea.ntnu.no (merke.itea.ntnu.no [129.241.7.61]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6020743CED for ; Thu, 14 Dec 2006 22:55:30 +0000 (GMT) (envelope-from lulf@stud.ntnu.no) Received: from localhost (localhost [127.0.0.1]) by merke.itea.ntnu.no (Postfix) with ESMTP id 44C9513C7C3; Thu, 14 Dec 2006 23:56:51 +0100 (CET) Received: from studby.ntnu.no (m044h.studby.ntnu.no [129.241.135.44]) by merke.itea.ntnu.no (Postfix) with ESMTP; Thu, 14 Dec 2006 23:56:51 +0100 (CET) Received: by studby.ntnu.no (Postfix, from userid 1001) id 2CFF8398E2; Thu, 14 Dec 2006 23:56:55 +0100 (CET) Date: Thu, 14 Dec 2006 23:56:54 +0100 From: Ulf Lilleengen To: Olivier Cochard-Labbe Message-ID: <20061214225654.GA14991@vimes.studby.ntnu.no> References: <3131aa530612110522y7b8ccad5k9d5735277b4d5ffa@mail.gmail.com> <20061211164844.GA3827@vimes.studby.ntnu.no> <3131aa530612130145l77ebb6f6ga7d4ac54716b5cc0@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3131aa530612130145l77ebb6f6ga7d4ac54716b5cc0@mail.gmail.com> User-Agent: Mutt/1.4.2.2i X-Content-Scanned: with sophos and spamassassin at mailgw.ntnu.no. Cc: freebsd-geom@freebsd.org Subject: Re: geom raid5 module X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 14 Dec 2006 23:05:51 -0000 On ons, des 13, 2006 at 10:45:14am +0100, Olivier Cochard-Labbe wrote: > Here is, for example, the first problem problem with geom vinum RAID5: > > I have 4 disks: > - ad0: 203MB > - ad1: 101MB > - ad2: 306MB > - ad3: 101MB > > If I create a raid 5 volume with these disk, can you confirme that the > theorical size should be 300MB (4 disks of the smallest drive: 100MB) > ? It's the size given with graid5 and with RAID caclulator > (http://dorm.tunkeymicket.com/raidcalc/). > But with geom vinum I obtain a 611MB disk: > Hi, I found the "bug"! The thing is that gvinum sets the plex-size after the last subdisk created instead of the smallest. I started to make a fix to make it set it to the lowest, but then I began thinking. You should not make different-sized subdisks in a raid5 configuration. Then I discovered this is "fixed" in CURRENT, by giving you an error when you try to create a raid5 volume with different-sized subdisks. And I think this makes sense. If you create a raid5-volume, all subdisks should be the same size. However, I'm thinking of maybe make gvinum be more "autodetectable" on this upon creation by actually examining which subdisk is smallest when you give it a raid5 plex with different-sized subdisks. I'll look more into your second problem tomorrow :) -- Ulf Lilleengen