From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from casper.infradead.org ([85.118.1.10]:38787 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751466Ab2FOGt4 (ORCPT ); Fri, 15 Jun 2012 02:49:56 -0400 Message-ID: <4FDADB0C.5040308@kernel.dk> Date: Fri, 15 Jun 2012 08:49:48 +0200 From: Jens Axboe MIME-Version: 1.0 Subject: Re: FIO r/w to 2 disks References: <4E57E183169EA04186759995F13BDC621A18A7C7@FMSMSX103.amr.corp.intel.com> <4FD998CE.3030705@kernel.dk> <4E57E183169EA04186759995F13BDC6234F46FA9@FMSMSX103.amr.corp.intel.com> In-Reply-To: <4E57E183169EA04186759995F13BDC6234F46FA9@FMSMSX103.amr.corp.intel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: "Strickland, Carl" Cc: "fio@vger.kernel.org" On 06/15/2012 01:41 AM, Strickland, Carl wrote: > Hi Jens, > > The test I'm interested in performing would require (I believe) FIO to > read from one device and write to another in a specified ratio. This > is different from the rwmix feature in FIO, as I can specify only a > single device where the reads and writes will take place. > > Assuming that I could achieve the same read/write ratio with two FIO > instances (one reading from one device and the other writing to a > different device) as I get using a single FIO instance and rwmix, is > there a reason--in terms of how reads and writes would be > performed--that would prevent a valid comparison between the two? Maybe the flow options would help you? Set up two jobs in a single file, one reader and one writer. Set up the flow parameters to get your desired split. See HOWTO, and/or examples/flow to get an idea for how to use that. -- Jens Axboe