From owner-freebsd-fs Fri Jan 31 11:56:20 2003 Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9C9DA37B401; Fri, 31 Jan 2003 11:56:18 -0800 (PST) Received: from apollo.email.starband.net (smtp2.starband.net [148.78.247.23]) by mx1.FreeBSD.org (Postfix) with ESMTP id D9E5D43F43; Fri, 31 Jan 2003 11:56:17 -0800 (PST) (envelope-from jkirby@storagecraft.com) Received: from jkirbydesk (vsat-148-63-114-177.c002.t7.mrt.starband.net [148.63.114.177]) (authenticated bits=0) by apollo.email.starband.net (8.12.4/8.12.4) with ESMTP id h0VJtTH5005007; Fri, 31 Jan 2003 14:55:37 -0500 Reply-To: From: "Jamey Kirby" To: "'Julian Elischer'" , "'Steve Byan'" Cc: , , Subject: RE: DEV_B_SIZE Date: Fri, 31 Jan 2003 11:55:33 -0800 Organization: StorageCraft Message-ID: <000601c2c962$c04aa2d0$0300a8c0@jkirbydesk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4024 In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Importance: Normal Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Who will do the translation? Will there be a device driver that makes the 4K disk look like a 512 byte disk? If so, the device driver would have to pre-read the 4K, modify the 512 byte section and re-write the entire 4K. This would kill performance. If this will be handled in the drive, the same sort of logic must be employed and surly there will be a performance problem; unless the drive will be able to write the 512 bytes without a pre-read. How easy is it to change the firmware in the drive to make it a 4K block drive? I would be willing to tinker with a 4K drive and provide some feedback. Jamey -----Original Message----- From: owner-freebsd-fs@FreeBSD.ORG [mailto:owner-freebsd-fs@FreeBSD.ORG] On Behalf Of Julian Elischer Sent: Friday, January 31, 2003 11:49 AM To: Steve Byan Cc: phk@FreeBSD.ORG; freebsd-fs@FreeBSD.ORG; tech-kern@netbsd.org Subject: Re: DEV_B_SIZE One thign I thought of is that it is not uncommon to 'dd' an entire filesystem from one partition to another. If we create a filesystem that is 'aligned' and we copy it to be 'unalligned', we'd have a sudden performance drop for no immediatly obvious reason. What was one write, would become a 2-sector read, modify and 2-sector write. Especially when copying from one failing drive to another with slightly different characteristics. The idea isn't bad but I think it should be sold as a 4k sector drive, with small print saying it can handle 512byte IO instead of the other way around. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message