Date: Sun, 12 Aug 2001 18:33:24 +0930 From: Greg Lehey <grog@FreeBSD.org> To: Alfred Perlstein <bright@mu.org> Cc: Kevin Hui <khui@cs.toronto.edu>, freebsd-questions@freebsd.org Subject: Re: Experiencing very slow raw write speeds on /dev/ad1 Message-ID: <20010812183324.F48115@wantadilla.lemis.com> In-Reply-To: <20010812033705.V85642@elvis.mu.org>; from bright@mu.org on Sun, Aug 12, 2001 at 03:37:05AM -0500 References: <20010810025156.N85642@elvis.mu.org> <Pine.GSO.4.21.0108101106250.9706-100000@gardiner.cs> <20010812180014.D48115@wantadilla.lemis.com> <20010812033705.V85642@elvis.mu.org>
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On Sunday, 12 August 2001 at 3:37:05 -0500, Alfred Perlstein wrote: > * Greg Lehey <grog@FreeBSD.org> [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
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