From owner-freebsd-fs Fri Jan 31 11:58:39 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 120A537B401 for ; Fri, 31 Jan 2003 11:58:38 -0800 (PST) Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id 1774943F3F for ; Fri, 31 Jan 2003 11:58:37 -0800 (PST) (envelope-from phk@freebsd.org) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.12.6/8.12.6) with ESMTP id h0VJwR4W031672; Fri, 31 Jan 2003 20:58:28 +0100 (CET) (envelope-from phk@freebsd.org) To: Julian Elischer Cc: Steve Byan , freebsd-fs@freebsd.org, tech-kern@netbsd.org Subject: Re: DEV_B_SIZE From: phk@freebsd.org In-Reply-To: Your message of "Fri, 31 Jan 2003 11:48:56 PST." Date: Fri, 31 Jan 2003 20:58:27 +0100 Message-ID: <31671.1044043107@critter.freebsd.dk> 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 In message , Ju lian Elischer writes: > > >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. If you run dd without bs=ALOT you deserve bad throughput. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message