From owner-freebsd-questions Sun Aug 12 2: 3: 2 2001 Delivered-To: freebsd-questions@freebsd.org Received: from wantadilla.lemis.com (wantadilla.lemis.com [192.109.197.80]) by hub.freebsd.org (Postfix) with ESMTP id 914D637B407 for ; Sun, 12 Aug 2001 02:02:58 -0700 (PDT) (envelope-from grog@lemis.com) Received: by wantadilla.lemis.com (Postfix, from userid 1004) id 06AE46ACBF; Sun, 12 Aug 2001 18:33:25 +0930 (CST) Date: Sun, 12 Aug 2001 18:33:24 +0930 From: Greg Lehey To: Alfred Perlstein Cc: Kevin Hui , freebsd-questions@freebsd.org Subject: Re: Experiencing very slow raw write speeds on /dev/ad1 Message-ID: <20010812183324.F48115@wantadilla.lemis.com> References: <20010810025156.N85642@elvis.mu.org> <20010812180014.D48115@wantadilla.lemis.com> <20010812033705.V85642@elvis.mu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20010812033705.V85642@elvis.mu.org>; from bright@mu.org on Sun, Aug 12, 2001 at 03:37:05AM -0500 Organization: The FreeBSD Project Phone: +61-8-8388-8286 Fax: +61-8-8388-8725 Mobile: +61-418-838-708 WWW-Home-Page: http://www.FreeBSD.org/ X-PGP-Fingerprint: 6B 7B C3 8C 61 CD 54 AF 13 24 52 F8 6D A4 95 EF Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Sunday, 12 August 2001 at 3:37:05 -0500, Alfred Perlstein wrote: > * Greg Lehey [010812 03:29] wrote: >> >> Linux and rawio are not really compatible. In Linux you have no >> choice, you must go via buffer cache; this can give you results which >> look much better. Also, sequential I/O is not very informative, >> especially if you only have one process. It would be much more >> interesting to look at random I/O and not change the default rawio >> parameters (in particular, let 8 concurrent processes run). > > I was going to say that (linux cheats because it doesn't really have > raw io), but I wasn't sure I was up to date enough. Well, to be *really* up to date, sct has patches for 2.4, confusingly called rawio, which do supply character disk devices to Linux. I don't know how to get them, though. Greg -- When replying to this message, please copy the original recipients. If you don't, I may ignore the reply. For more information, see http://www.lemis.com/questions.html See complete headers for address and phone numbers To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message