From owner-freebsd-scsi Sun Mar 21 14: 4:24 1999 Delivered-To: freebsd-scsi@freebsd.org Received: from misery.sdf.com (misery.sdf.com [204.244.213.49]) by hub.freebsd.org (Postfix) with SMTP id 607E915207 for ; Sun, 21 Mar 1999 14:04:21 -0800 (PST) (envelope-from tom@sdf.com) Received: from tom by misery.sdf.com with esmtp (Exim 1.82 #3) id 10OpJ1-0006Jz-00; Sun, 21 Mar 1999 12:58:47 -0800 Date: Sun, 21 Mar 1999 12:58:46 -0800 (PST) From: Tom To: Nick Hilliard Cc: Greg Lehey , freebsd-scsi@FreeBSD.ORG Subject: Re: dpt raid-5 performance In-Reply-To: <199903211417.OAA28733@beckett.earlsfort.iol.ie> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org On Sun, 21 Mar 1999, Nick Hilliard wrote: > > I haven't yet replied to Nick's message because I wanted to check > > something here first, and I've been too busy so far. But I'll come > > back with some comparisons. > > I'm going to run some benchmarks over the next few days and see what they > throw up. > > My instinct was that 512K was a "good" interleave size in some sense of the > word, mainly because of the fact that it would cause so many fewer disk io > ops in most circumstances -- in fact, all circumstances except where you're > doing piles of tiny io ops. The bonnie results seem to shatter this > illusion. Uhh... no. Large stripe sizes for good for lots of parallel processes. Bonnie is only a single process, so you would want to break each disk i/o into multiple requests to maximize its performance (after all the array doesn't have anything else to do). Optimizing for multi-user is very different from single-user. > Does anyone know if a 2044W card creates exactly the same RAID structure on > a disk array as a 3334UW? I have both cards lying around the place at the > moment, and it would trivial to run benchmarks for both systems just by > replacing the card on the machine. The 3334UW has a faster processor. The I/Os per second can be looked up. > Nick Hilliard > Ireland On-Line System Operations Tom To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message