From owner-freebsd-scsi Sat Mar 20 13:16:41 1999 Delivered-To: freebsd-scsi@freebsd.org Received: from allegro.lemis.com (allegro.lemis.com [192.109.197.134]) by hub.freebsd.org (Postfix) with ESMTP id 18FF414A2F for ; Sat, 20 Mar 1999 13:16:36 -0800 (PST) (envelope-from grog@freebie.lemis.com) Received: from freebie.lemis.com (freebie.lemis.com [192.109.197.137]) by allegro.lemis.com (8.9.1/8.9.0) with ESMTP id HAA09701; Sun, 21 Mar 1999 07:46:15 +1030 (CST) Received: (from grog@localhost) by freebie.lemis.com (8.9.3/8.9.0) id HAA89826; Sun, 21 Mar 1999 07:46:13 +1030 (CST) Message-ID: <19990321074613.V429@lemis.com> Date: Sun, 21 Mar 1999 07:46:13 +1030 From: Greg Lehey To: Tom , Nick Hilliard Cc: freebsd-scsi@FreeBSD.ORG Subject: Re: dpt raid-5 performance References: <199903191422.OAA27845@beckett.earlsfort.iol.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 0.93.2i In-Reply-To: ; from Tom on Sat, Mar 20, 1999 at 08:55:27AM -0800 WWW-Home-Page: http://www.lemis.com/~grog Organization: LEMIS, PO Box 460, Echunga SA 5153, Australia Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-41-739-7062 Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Saturday, 20 March 1999 at 8:55:27 -0800, Tom wrote: > > On Fri, 19 Mar 1999, Nick Hilliard wrote: > >> If I set up a raid-5 system on these disks with a slice-size of 512K, the >> write performance is terrible. Bonnie reports: > > 512k will not result in very good single process write performance. > In fact, 512k is suboptimal for many operations on RAID-5 arrays. I disagree. It's pretty much optimal for Vinum. I'd be interested in your reasoning. > If you are optimizing for a single process, use something smaller > (like 8k). That's far, far too small. Greg -- See complete headers for address, home page and phone numbers finger grog@lemis.com for PGP public key To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message