From owner-freebsd-performance@FreeBSD.ORG Tue Sep 28 12:45:10 2010 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5F68A10656C2 for ; Tue, 28 Sep 2010 12:45:10 +0000 (UTC) (envelope-from ssanders@softhammer.net) Received: from oproxy3-pub.bluehost.com (oproxy3-pub.bluehost.com [69.89.21.8]) by mx1.freebsd.org (Postfix) with SMTP id 2DA9F8FC21 for ; Tue, 28 Sep 2010 12:45:09 +0000 (UTC) Received: (qmail 13559 invoked by uid 0); 28 Sep 2010 12:45:09 -0000 Received: from unknown (HELO host358.hostmonster.com) (66.147.240.158) by oproxy3.bluehost.com with SMTP; 28 Sep 2010 12:45:09 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=default; d=softhammer.net; h=Received:Message-ID:Date:From:User-Agent:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding:X-Identified-User; b=uuI22gSJOvrdTSnpgMIhLF948V8q+FqUSbKldXW1ylFG3hcv3c1769I1Rs1OftA4E9bxqY10U1Bs2jxQWEO7WqwRAE17rV6eU1iSVeILVHp289ScspX2l1d+WOr6UCVi; Received: from pool-74-96-233-244.washdc.fios.verizon.net ([74.96.233.244] helo=[192.168.1.54]) by host358.hostmonster.com with esmtpa (Exim 4.69) (envelope-from ) id 1P0ZYT-0006DG-96; Tue, 28 Sep 2010 06:45:09 -0600 Message-ID: <4CA1E354.8000608@softhammer.net> Date: Tue, 28 Sep 2010 08:45:08 -0400 From: Stephen Sanders User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc13 Thunderbird/3.1.4 MIME-Version: 1.0 To: Alexander Motin References: <4CA180FD.9050002@FreeBSD.org> In-Reply-To: <4CA180FD.9050002@FreeBSD.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Identified-User: {2492:host358.hostmonster.com:softhamm:softhammer.net} {sentby:smtp auth 74.96.233.244 authed with ssanders@softhammer.net} Cc: freebsd-performance@freebsd.org Subject: Re: gstripe small transaction size X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 28 Sep 2010 12:45:10 -0000 Ooops, didn't put out the particulars of the system. This is a FreeBSD 8.0 system that has not been updated. We upped the block size of the da driver, not MAXPHYS. I'll give that a shot. Thanks. On 09/28/2010 01:45 AM, Alexander Motin wrote: > Stephen Sanders wrote: >> I'm trying a disk throughput experiment where in two 3ware raid 6's are >> being put into a g_strip raid 0. >> >> The raid 6's are using 8 7200RPM disks. The disk transfer rate is >> ~80MB/s. Using a load generation tool that is using O_DIRECT for I/O, >> I've generated the following short output from iostat. Needless to say, >> the write performance is a lot less than I'm expecting. >> >> We've modified the kernel such that our KB/t figure is closer to 512KB/t >> per disk when measured without the g_strip. With g_strip turned on, the >> KB/t number is more like 60KB/t. >> >> The question is how do I get g_stripe to write larger transactions to >> the disk ? > How old is your system? There was bug, fixed 8-12 months ago, making > fast mode in gstripe not working on systems with increased MAXPHYS. As I > understand, it is what you've changed in your kernel. >