From owner-freebsd-hackers Wed Mar 4 11:07:42 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA28693 for freebsd-hackers-outgoing; Wed, 4 Mar 1998 11:07:42 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from sendero.simon-shapiro.org (sendero-fxp0.Simon-Shapiro.ORG [206.190.148.34]) by hub.freebsd.org (8.8.8/8.8.8) with SMTP id LAA28675 for ; Wed, 4 Mar 1998 11:07:37 -0800 (PST) (envelope-from shimon@sendero-fxp0.simon-shapiro.org) Received: (qmail 8449 invoked by uid 1000); 4 Mar 1998 19:14:28 -0000 Message-ID: X-Mailer: XFMail 1.3-alpha-021598 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <19980304081523.61560@mcs.net> Date: Wed, 04 Mar 1998 11:14:28 -0800 (PST) Reply-To: shimon@simon-shapiro.org Organization: The Simon Shapiro Foundation From: Simon Shapiro To: Karl Denninger Subject: Re: SCSI Bus redundancy... Cc: grog@lemis.com, hackers@FreeBSD.ORG, blkirk@float.eli.net, jdn@acp.qiv.com, tlambert@primenet.com, sbabkin@dcn.att.com, Wilko Bulte Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 04-Mar-98 Karl Denninger wrote: ... > Hmmm.... Well, I made some adjustments to the queueing algorythm in the > controller this morning, and guess what - I now get ~17MB/Sec on two SCSI > busses in RAID 0+1 mode. Now *that's* not bad. In RAID 5 mode I'm > getting > ~10MB/sec still, and I think I'm hitting the wall now on the disk I/O > (since > RAID 5 doesn't stripe data) rather than on the interface! These are good numbers. Play with RAID-5 stripe size. You may see jumps in perfromance. > Curiously enough, turning read-ahead in the controller on actually slows > it *down* a bit. Not much, but a little bit. Of course. For RAID-5 it is normal. I set the DPT to ZERO. Simon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message