From owner-freebsd-stable@FreeBSD.ORG Mon Jun 27 03:19:24 2005 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 7B7AC16A420 for ; Mon, 27 Jun 2005 03:19:24 +0000 (GMT) (envelope-from serg@tmn.ru) Received: from sbtx.tmn.ru (sbtx.tmn.ru [212.76.160.49]) by mx1.FreeBSD.org (Postfix) with ESMTP id B7F6743D55 for ; Mon, 27 Jun 2005 03:19:21 +0000 (GMT) (envelope-from serg@tmn.ru) Received: from sv.tech.sibitex.tmn.ru (sv.tech.sibitex.tmn.ru [10.76.160.59]) by sbtx.tmn.ru (8.13.3/8.13.3) with ESMTP id j5R3JJ25046082; Mon, 27 Jun 2005 09:19:19 +0600 (YEKST) (envelope-from serg@tmn.ru) Received: from sv.tech.sibitex.tmn.ru (localhost.tech.sibitex.tmn.ru [127.0.0.1]) by sv.tech.sibitex.tmn.ru (8.13.3/8.13.3) with ESMTP id j5R3JJZK020326; Mon, 27 Jun 2005 09:19:19 +0600 (YEKST) (envelope-from serg@sv.tech.sibitex.tmn.ru) Received: (from serg@localhost) by sv.tech.sibitex.tmn.ru (8.13.3/8.13.3/Submit) id j5R3JJKD020325; Mon, 27 Jun 2005 09:19:19 +0600 (YEKST) (envelope-from serg) Date: Mon, 27 Jun 2005 09:19:18 +0600 From: "Sergey N. Voronkov" To: "Marc G. Fournier" Message-ID: <20050627031918.GA20199@tmn.ru> References: <20050626233114.G57847@ganymede.hub.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050626233114.G57847@ganymede.hub.org> User-Agent: Mutt/1.4.2.1i X-Virus-Scanned: ClamAV version 0.86.1, clamav-milter version 0.86 on sbtx.tmn.ru X-Virus-Status: Clean Cc: freebsd-stable@freebsd.org Subject: Re: SATA vs SCSI ... X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Jun 2005 03:19:24 -0000 On Sun, Jun 26, 2005 at 11:34:22PM -0300, Marc G. Fournier wrote: > > looking at the specs between two cards, the SATA card(s) seem to rate > ~100-150MB/s on each channel (if I'm reading right), with both the 3Ware > and ICP cards having 4 individual channels ... looking at the SCSI cards, > they are rated at 320MB/s, but that is total for the SCSI bus itself, > right? It is dependant of the card too. You can get a 3 channel Ultra320 card for 3 drive RAID 5... > So, if I have three drives on a SCSI bus, each 'maxing out evenly', I'd > be cap'd at about the same 100MB/s per drive, no? > > In fact, looking at the SATA 2.x specs, each chanell there is rated at > 300MB/s, which, again, if I could 'max out evenly', could seriously blow > away the SCSI bus itself ... That is a theory... > *If* I'm reading this right ... ? And now from my practice: 1) You CAN'T get maximal throuput from 150/160 MB/s bus - the is no such drives today at the market. 2) Avg. seek and access time of 7200 SATA drives are FAR BELOW such of old Seagate Cheetah/Maxtor Athlas 10K. So is a situation with a WD Raptor 10K SATA too - they are SLOWER! (I'm not shure why, but from my test: 2xPIII-1.4/1G RAM/2x36G Cheeta 10K in RAID 1 (AMR Express; One U160 channel) ws. 2xXeon 3.0/2G RAM/2x72G Raptor in RAID 1 (Intel SRCS16; Separate SATA-150 channel for each drive) Ports three checkout is about 20% faster on the first comp. As an result: If you need to have FAST disk subsystem - buy SCSI. If you need large storage or you don't want to pay to much money - buy SATA. Best Ragards, Serg N. Voronkov, Sibitex JSC.