From owner-freebsd-stable Sun Jul 2 17:42:59 2000 Delivered-To: freebsd-stable@freebsd.org Received: from sabre.velocet.net (sabre.velocet.net [198.96.118.66]) by hub.freebsd.org (Postfix) with ESMTP id 3E29D37BD7F for ; Sun, 2 Jul 2000 17:42:57 -0700 (PDT) (envelope-from dgilbert@office.tor.velocet.net) Received: from office.tor.velocet.net (trooper.velocet.net [216.126.82.226]) by sabre.velocet.net (Postfix) with ESMTP id 7B840137F49; Sun, 2 Jul 2000 20:42:54 -0400 (EDT) Received: (from dgilbert@localhost) by office.tor.velocet.net (8.9.3/8.9.3) id UAA97472; Sun, 2 Jul 2000 20:42:54 -0400 (EDT) (envelope-from dgilbert) From: David Gilbert MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <14687.57741.726207.302060@trooper.velocet.net> Date: Sun, 2 Jul 2000 20:42:53 -0400 (EDT) To: Kent Stewart Cc: David Gilbert , freebsd-stable@freebsd.org Subject: Re: Dump takes ages on SCSI. (several times faster on IDE) In-Reply-To: <395FB9EA.E3115939@3-cities.com> References: <14687.42282.873585.2561@trooper.velocet.net> <395FB9EA.E3115939@3-cities.com> X-Mailer: VM 6.75 under 20.4 "Emerald" XEmacs Lucid Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG >>>>> "Kent" == Kent Stewart writes: >> I then noticed that the IDE would crashdump somewhere around 10 >> times faster than the SCSI disk. >> >> Why? Can the SCSI speed be improved? Kent> It depends on what 2940 and what IDE drive you are talking Kent> about. I have a Maxtor UDMA66 that is 20MB/s faster in some I don't think this explains it at all. It would appear that the SCSI driver is running in some "extra safe" mode, or something. It has 512M to write sequentually to a partition... and the counting on the screen, we're looking at 2 to 3 seconds-per-megabyte (on a drive that delivers write performance of about 10M/s in normal operation). Maybe what I should have said that the ratio of regular operation to dump performance of the ide driver is about 1:1 while it's 10:1 for the SCSI driver... why is this? Dave. -- ============================================================================ |David Gilbert, Velocet Communications. | Two things can only be | |Mail: dgilbert@velocet.net | equal if and only if they | |http://www.velocet.net/~dgilbert | are precisely opposite. | =========================================================GLO================ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message