From owner-freebsd-questions@FreeBSD.ORG Wed Oct 8 09:45:19 2008 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 802B8106568E for ; Wed, 8 Oct 2008 09:45:19 +0000 (UTC) (envelope-from talon@lpthe.jussieu.fr) Received: from shiva.jussieu.fr (shiva.jussieu.fr [134.157.0.129]) by mx1.freebsd.org (Postfix) with ESMTP id EC13D8FC19 for ; Wed, 8 Oct 2008 09:45:18 +0000 (UTC) (envelope-from talon@lpthe.jussieu.fr) Received: from parthe.lpthe.jussieu.fr (parthe.lpthe.jussieu.fr [134.157.10.1]) by shiva.jussieu.fr (8.14.3/jtpda-5.4) with ESMTP id m989jG8T033400 for ; Wed, 8 Oct 2008 11:45:16 +0200 (CEST) X-Ids: 168 Received: from niobe.lpthe.jussieu.fr (niobe.lpthe.jussieu.fr [134.157.10.41]) by parthe.lpthe.jussieu.fr (Postfix) with ESMTP id 175A98A0AD for ; Wed, 8 Oct 2008 11:45:15 +0200 (CEST) Received: by niobe.lpthe.jussieu.fr (Postfix, from userid 2005) id 0A47510A; Wed, 8 Oct 2008 11:45:15 +0200 (CEST) Date: Wed, 8 Oct 2008 11:45:14 +0200 From: Michel Talon To: freebsd-questions@freebsd.org Message-ID: <20081008094514.GA96151@lpthe.jussieu.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.4.2.3i X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (shiva.jussieu.fr [134.157.0.168]); Wed, 08 Oct 2008 11:45:16 +0200 (CEST) X-Virus-Scanned: ClamAV 0.93.3/8394/Wed Oct 8 06:15:25 2008 on shiva.jussieu.fr X-Virus-Status: Clean X-Miltered: at jchkmail.jussieu.fr with ID 48EC812C.002 by Joe's j-chkmail (http : // j-chkmail dot ensmp dot fr)! X-j-chkmail-Enveloppe: 48EC812C.002/134.157.10.1/parthe.lpthe.jussieu.fr/parthe.lpthe.jussieu.fr/ X-j-chkmail-Score: MSGID : 48EC812C.002 on jchkmail.jussieu.fr : j-chkmail score : . : R=. U=. O=. B=0.033 -> S=0.033 X-j-chkmail-Status: Ham Subject: Re: adding a slice to gmirror instead of a whole disk, will it work? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 08 Oct 2008 09:45:19 -0000 Craig Butler wrote: > Will adding a slice to a gmirror instead of a whole disk work? > The slice is big enough to accommodate the old disk. It will work no problem. The only possible trouble is to have the last sector of the disk or slice free to be able to put the geom marker on it. For example i have a mirror with 2 slices: asmodee% gmirror list Geom name: gms1 State: COMPLETE Components: 2 Balance: load Slice: 4096 Flags: NONE GenID: 0 SyncID: 2 ID: 1193348252 Providers: 1. Name: mirror/gms1 Mediasize: 16776699904 (16G) Sectorsize: 512 Mode: r5w5e5 Consumers: 1. Name: ad0s1 Mediasize: 16776700416 (16G) Sectorsize: 512 Mode: r1w1e1 State: ACTIVE Priority: 0 Flags: DIRTY GenID: 0 SyncID: 2 ID: 1158494643 2. Name: ad4s1 Mediasize: 16776700416 (16G) Sectorsize: 512 Mode: r1w1e1 State: ACTIVE Priority: 0 Flags: DIRTY GenID: 0 SyncID: 2 ID: 2277636746 Note that in this case (one of the disks is slower than the other) i observed that the "round-robin" strategy was giving poor results (slower than the slowest of the two disks) while the "load" strategy gives performance like the faster disk. Consumers can be absolutely anything, this is the beauty of the GEOM idea. -- Michel TALON