From owner-freebsd-fs@FreeBSD.ORG Tue Jun 23 03:29:29 2015 Return-Path: Delivered-To: freebsd-fs@nevdull.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B968DDCB for ; Tue, 23 Jun 2015 03:29:29 +0000 (UTC) (envelope-from quartz@sneakertech.com) Received: from douhisi.pair.com (douhisi.pair.com [209.68.5.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 9432CF5 for ; Tue, 23 Jun 2015 03:29:29 +0000 (UTC) (envelope-from quartz@sneakertech.com) Received: from [10.2.2.1] (pool-173-48-121-235.bstnma.fios.verizon.net [173.48.121.235]) by douhisi.pair.com (Postfix) with ESMTPSA id 2703B3F6DD; Mon, 22 Jun 2015 23:29:22 -0400 (EDT) Message-ID: <5588D291.4030806@sneakertech.com> Date: Mon, 22 Jun 2015 23:29:21 -0400 From: Quartz User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:10.0.2) Gecko/20120216 Thunderbird/10.0.2 MIME-Version: 1.0 To: kpneal@pobox.com CC: FreeBSD FS Subject: Re: ZFS raid write performance? References: <5587C3FF.9070407@sneakertech.com> <5587C97F.2000407@delphij.net> <55887810.3080301@sneakertech.com> <20150622221422.GA71520@neutralgood.org> <55888E0D.6040704@sneakertech.com> <20150623002854.GB96928@neutralgood.org> In-Reply-To: <20150623002854.GB96928@neutralgood.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 23 Jun 2015 03:29:29 -0000 >> I guess a better way to word the question is: would a raidzX using >> generic drives, samba, and 500mb-4gb files be notably slower at writing >> than ~70mb/sec. I have a feeling not, but I wanted to double check. > > Gut feeling: I'm sticking with the network being the limiting factor. > But the only real way to know is to setup a test system and, well, test. Question: I'm not super familiar with the way freebsd+zfs handles IO and caching under the hood, especially not when you throw drive caching into the mix too. Does something simple like "dd if=/dev/zero of=/pool/foo bs=1m count=500" give me a reasonably accurate number for write speed?