Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753200AbYFAL0W (ORCPT ); Sun, 1 Jun 2008 07:26:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751793AbYFAL0L (ORCPT ); Sun, 1 Jun 2008 07:26:11 -0400 Received: from lucidpixels.com ([75.144.35.66]:32786 "EHLO lucidpixels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751722AbYFAL0K (ORCPT ); Sun, 1 Jun 2008 07:26:10 -0400 Date: Sun, 1 Jun 2008 07:26:09 -0400 (EDT) From: Justin Piszcz To: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, xfs@oss.sgi.com Subject: Re: Limits of the 965 chipset & 3 PCI-e cards/southbridge? ~774MiB/s peak for read, ~650MiB/s peak for write? In-Reply-To: Message-ID: References: User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1850 Lines: 54 On Sun, 1 Jun 2008, Justin Piszcz wrote: > > On Sun, 1 Jun 2008, Justin Piszcz wrote: > >> I have 12 enterprise-class seagate 1TiB disks on a 965 desktop board and it >> appears I have hit the limit, if I were able to get the maximum speed of >> all drives, ~70MiB/avg * 12 = 840MiB/s but it seems to stop aound 774 MiB/s >> (currently running badblocks on all drives).. > > Small correction, they are 7200.11 Seagate Desktop Drives (ST31000340AS), not > enterprise drives: > > http://www.seagate.com/ww/v/index.jsp?vgnextoid=0732f141e7f43110VgnVCM100000f5ee0a0aRCRD > http://www.newegg.com/Product/Product.aspx?Item=N82E16822148274 > > http://www.intel.com/products/chipsets/g965/diagram.jpg Basically it appears I am hammering the southbridge as for this board the PCI-e (x1) slots also traverse through the southbridge. 6_SATA -> G965 ICH8 3_PCI-e -> G965 ICH8 >From which has to ship that data across the DMI (2GB) link to the northbridge. If one utilized a 12, 16 or 24 port raid card (but used SW RAID) on the x16 slot on the northbridge itself, would this barrier exist as the: GMCH<->CPU is (8.5GB/s)..? Also on the X38 and X48 the speed increases slightly: http://www.intel.com/products/chipsets/X38/X38_Block_Diagram.jpg (10.6GB/s) http://www.intel.com/products/chipsets/x48/x48_block_diagram.jpg (12.8GB/s) If one asks why would one need such speed? Example: LTO-4 drives can write at 120 MiB/s each: http://en.wikipedia.org/wiki/Linear_Tape-Open It is then therefore imperative one could sustain this rate to possibly multiple(!) tape drives on a single system. Justin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/