From owner-cvs-all@FreeBSD.ORG Tue Aug 17 13:44:07 2004 Return-Path: Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C865016A5BA; Tue, 17 Aug 2004 13:44:07 +0000 (GMT) Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.86.163]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2E95143D2D; Tue, 17 Aug 2004 13:44:07 +0000 (GMT) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.13.1/8.13.1) with ESMTP id i7HDi4xK041450; Tue, 17 Aug 2004 15:44:04 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: Wilko Bulte From: "Poul-Henning Kamp" In-Reply-To: Your message of "Tue, 17 Aug 2004 15:27:40 +0200." <20040817132740.GA32139@freebie.xs4all.nl> Date: Tue, 17 Aug 2004 15:44:04 +0200 Message-ID: <41449.1092750244@critter.freebsd.dk> Sender: phk@critter.freebsd.dk cc: Greg 'groggy' Lehey cc: cvs-src@FreeBSD.org cc: src-committers@FreeBSD.org cc: Pawel Jakub Dawidek cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src MAINTAINERS X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Aug 2004 13:44:07 -0000 In message <20040817132740.GA32139@freebie.xs4all.nl>, Wilko Bulte writes: >RAID-3 IIRC uses a dedicated parity disk, and small stripes. I don't think >it must be bytelevel striping. Just small enough stripes that all disks >contribute to every I/O RAID3 differs from RAID5 in that you always access the entire stripe and never have R/M/W cycles. Typically the problem is that by doing so you get a RAID3 sectorsize which is the sum of all non-parity sectors, a 4+1 will give you 4 x 512 = 2048 and 8 + 3 will give you 4k. Since a lot of filesystems/OS/hardware can only work with 512 byte sectors, people have hacked around this in various ways and eventually given up on RAID3. UFS/FFS works fine with 1k, 2k, 4k and larger sectorsizes and so RAID3 is a great idea for FreeBSD, and I'd rather use RAID3 than RAID5 myself. -- 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.