From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 2 May 2002 17:14:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 2 May 2002 17:14:01 -0400 Received: from unthought.net ([212.97.129.24]:42133 "HELO mail.unthought.net") by vger.kernel.org with SMTP id ; Thu, 2 May 2002 17:14:00 -0400 Date: Thu, 2 May 2002 23:13:59 +0200 From: =?iso-8859-1?Q?Jakob_=D8stergaard?= To: Alan Cox Cc: Martin Dalecki , Pavel Machek , Roy Sigurd Karlsbakk , linux-kernel@vger.kernel.org Subject: Re: IDE hotplug support? Message-ID: <20020502231359.W31556@unthought.net> Mail-Followup-To: =?iso-8859-1?Q?Jakob_=D8stergaard?= , Alan Cox , Martin Dalecki , Pavel Machek , Roy Sigurd Karlsbakk , linux-kernel@vger.kernel.org In-Reply-To: <20020502215833.V31556@unthought.net> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: Mutt/1.2i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 02, 2002 at 09:26:38PM +0100, Alan Cox wrote: > > >=20 > > > 8 x 130MBy/s >>>> PCI bus throughput... I would rather recommend > > > a classical RAID controller card for this kind of > > > setup. > > > > Because RAID controllers do not use the PCI bus ??? ;) > > The raid card transfers the data once, software raid once per device for > Raid 1/5 - thats a killer. For RAID-1 it's a killer (for writes), I agree. But I really doubt it would be so horrible for RAID-5 - after all, it's only one extra block (the parity block) for each N-1 blocks written (for an N disk RAID-5). The penalty should be less, the more disks you have in the array. But seriously, has anyone out there ever seen a hardware RAID controller with a *sustained* RAID-5 thoughput of more than 60 MB/sec ? Not that I think it is impossible, but I've never heard about it. Enlighten me, please, and not with marketing numbers... > > > By the way, has anyone tried such larger multi-controller setups, and t= > > ested > > the bandwidth in configurations with multiple PCI busses on the board, = > > versus a > > single PCI bus ? > > With 2.4 yes. With all the 2.5 changes no. Did you get any speedup ? Were you close to PCI bus saturation in the one-bus scenario ? -- ................................................................ : jakob@unthought.net : And I see the elder races, : :.........................: putrid forms of man : : Jakob Østergaard : See him rise and claim the earth, : : OZ9ABN : his downfall is at hand. : :.........................:............{Konkhra}...............: