From owner-freebsd-scsi Fri Dec 12 14:08:29 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id OAA29429 for freebsd-scsi-outgoing; Fri, 12 Dec 1997 14:08:29 -0800 (PST) (envelope-from owner-freebsd-scsi) Received: from ns1.dpt.com (ns1.dpt.com [206.138.241.7]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id OAA29424 for ; Fri, 12 Dec 1997 14:08:27 -0800 (PST) (envelope-from salyzyn_mark@dpt.com) Received: from bohica.bohica.dpt.com (bohica.dpt.com [198.242.63.84]) by ns1.dpt.com (8.7.4/8.7.3) with SMTP id SAA03437 for ; Fri, 12 Dec 1997 18:12:06 -0500 Received: by bohica.bohica.dpt.com [198.242.63.84] (NX5.67f2/NX3.0M) id AA20739; Fri, 12 Dec 97 17:09:09 -0500 Message-Id: <9712122209.AA20739@bohica.bohica.dpt.com> Mime-Version: 1.0 (NeXT Mail 3.3 v118.2) Content-Type: text/plain; charset=us-ascii Received: by NeXT.Mailer (1.118.2) From: Mark Salyzyn Date: Fri, 12 Dec 97 17:09:08 -0500 To: freebsd-scsi@FreeBSD.ORG Subject: Re: RAID on FreeBSD Reply-To: salyzyn@dpt.com Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by hub.freebsd.org id OAA29425 Sender: owner-freebsd-scsi@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk In article <3.0.32.19971211155601.0092e580@gw1.tesys.com>, you wrote: >At 03:04 PM 12/11/97 -0800, Tom wrote: >>On Thu, 11 Dec 1997, Wilko Bulte wrote: >>> > 9 drives in an uncomfortable number for RAID5. Probably better to go >>> Why would 9 drives be uncomfartable? >> Well, if you are going to making one arrray of 9 drives, write >>performance will bad. If you are going to making 3 arrays of 3 >>drives each, you will end up with a lot of overhead. >> RAID5 arrays of 5 drives is kinda of nice sweet spot. If you go much >>bigger, just use RAID0 over multiple RAID5. >Please note that dual RAID support (dpt based) is not available under >FreeBSD(there are few other OS's which do support it), as per my >information.. Can someone verify that.. Software RAID is not available for the current driver by Simon. However, we have supplied Simon sources to a RAID-0 subsystem that he may add to the driver in the future. There is nothing preventing an OS RAID-0 from being set up, the only disadvantages are that it is not integrated into the DPT management solutions and you can not boot off of a dual level RAID device utilizing the second level within an OS driver. Sincerely -- Mark Salyzyn