From owner-freebsd-scsi@FreeBSD.ORG Tue May 13 16:57:12 2003 Return-Path: Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8937937B401 for ; Tue, 13 May 2003 16:57:12 -0700 (PDT) Received: from mobile.hub.org (u153n214.eastlink.ca [24.224.153.214]) by mx1.FreeBSD.org (Postfix) with ESMTP id 05D6643F93 for ; Tue, 13 May 2003 16:57:11 -0700 (PDT) (envelope-from scrappy@hub.org) Received: by mobile.hub.org (Postfix, from userid 1001) id 475981CD; Fri, 9 May 2003 22:25:51 -0300 (ADT) Received: from localhost (localhost [127.0.0.1]) by mobile.hub.org (Postfix) with ESMTP id 41FBB1C9 for ; Fri, 9 May 2003 22:25:51 -0300 (ADT) Date: Fri, 9 May 2003 22:25:51 -0300 (ADT) From: The Hermit Hacker To: freebsd-scsi@freebsd.org Message-ID: <20030509222154.N728@hub.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Subject: RAID5 capacities / usable drive space ... X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 May 2003 23:57:12 -0000 I have someone telling me something that I'd never heard before, and find difficult to believe ... Apparently, he is under the impression that altho a file system shows a capacity of, say, 100G, its usable space is around 50% of that ... anything higher then that, you risk problems ... (significantly reduced MTBF of the drives, degradation in performance, etc) ... His opinion seems to be based on some talks he had with ppl at IBM and Seagate way back in '89, but still seems to feel they are applicable today ... Is there any fact behind his opinion? If not, anything I can point him at to read? If so, anything I can be pointed at to read? Thanks ... Marc G. Fournier ICQ#7615664 IRC Nick: Scrappy Systems Administrator @ hub.org primary: scrappy@hub.org secondary: scrappy@{freebsd|postgresql}.org