From owner-freebsd-fs Sun Nov 8 22:25:34 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id WAA16491 for freebsd-fs-outgoing; Sun, 8 Nov 1998 22:25:34 -0800 (PST) (envelope-from owner-freebsd-fs@FreeBSD.ORG) Received: from pluto.plutotech.com (mail.plutotech.com [206.168.67.137]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id WAA16486 for ; Sun, 8 Nov 1998 22:25:33 -0800 (PST) (envelope-from gibbs@plutotech.com) Received: from narnia.plutotech.com (narnia.plutotech.com [206.168.67.130]) by pluto.plutotech.com (8.8.7/8.8.5) with ESMTP id XAA25317; Sun, 8 Nov 1998 23:24:22 -0700 (MST) Message-Id: <199811090624.XAA25317@pluto.plutotech.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Greg Lehey cc: "Justin T. Gibbs" , "Kenneth D. Merry" , bill@bilver.magicnet.net, freebsd-fs@FreeBSD.ORG Subject: Re: RAID1 Software vs Hardware In-reply-to: Your message of "Mon, 09 Nov 1998 14:26:01 +1030." <19981109142601.F499@freebie.lemis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sun, 08 Nov 1998 23:17:36 -0700 From: "Justin T. Gibbs" Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org >On Sunday, 8 November 1998 at 0:17:36 -0700, Justin T. Gibbs wrote: >>>> RAID 3 is still used, and is still useful. All of Pluto's products (see >>>> http://www.plutotech.com) use RAID 3. It works quite well for video data. >>> >>> I suppose it gives you good throughput. But how do you handle the I/O >>> load? Are you effectively delivering a single video stream? >> >> RAID 3 is ideal when your data requests are always a multiple of the strip >> size. > >I'm not sure we're talking about the same thing. In my book, RAID-3 >is a RAID-4 with a stripe size of 1 byte. How do you define it? RAID-3 confines parity to 1 member of the array. The size of the stripe is not a part of the specification. In the case of Pluto products, we usually use a stripe size of 1MB which implies a per-unit access of 1MB/N-1 (N being number of members in the RAID group). >Greg -- Justin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message