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 17:21:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 2 May 2002 17:21:56 -0400 Received: from [195.63.194.11] ([195.63.194.11]:49168 "EHLO mail.stock-world.de") by vger.kernel.org with ESMTP id ; Thu, 2 May 2002 17:21:55 -0400 Message-ID: <3CD19F19.2030104@evision-ventures.com> Date: Thu, 02 May 2002 22:18:33 +0200 From: Martin Dalecki User-Agent: Mozilla/5.0 (X11; U; Linux i686; pl-PL; rv:1.0rc1) Gecko/20020419 X-Accept-Language: en-us, pl MIME-Version: 1.0 To: =?ISO-8859-1?Q?Jakob_=D8stergaard?= CC: Alan Cox , Pavel Machek , linux-kernel@vger.kernel.org Subject: Re: IDE hotplug support? In-Reply-To: <20020502215833.V31556@unthought.net> <20020502231359.W31556@unthought.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Uz.ytkownik Jakob Østergaard napisa?: > 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... Go to Sun hardware and you will see it quite frequently even on a simple E450 equipped with an external RAID box. I saw them frequently enough in sar accounts when the system was configured to trash on a swap partition, which resided on such a RAID. 64 bit buses win here by a huge margin.