From owner-freebsd-fs@FreeBSD.ORG Wed Jun 12 16:03:40 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 628DC28D for ; Wed, 12 Jun 2013 16:03:40 +0000 (UTC) (envelope-from borjam@sarenet.es) Received: from proxypop03b.sare.net (proxypop03b.sare.net [194.30.0.251]) by mx1.freebsd.org (Postfix) with ESMTP id 285761855 for ; Wed, 12 Jun 2013 16:03:39 +0000 (UTC) Received: from [172.16.2.2] (izaro.sarenet.es [192.148.167.11]) by proxypop03.sare.net (Postfix) with ESMTPSA id 8B3959DD057; Wed, 12 Jun 2013 17:57:13 +0200 (CEST) Subject: Re: An order of magnitude higher IOPS needed with ZFS than UFS Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: text/plain; charset=us-ascii From: Borja Marcos In-Reply-To: <20130612114937.GA13688@icarus.home.lan> Date: Wed, 12 Jun 2013 17:57:13 +0200 Content-Transfer-Encoding: quoted-printable Message-Id: <8FF3DAC5-ED3D-4678-B040-74829A208A86@sarenet.es> References: <51B79023.5020109@fsn.hu> <20130612114937.GA13688@icarus.home.lan> To: Jeremy Chadwick X-Mailer: Apple Mail (2.1085) Cc: freebsd-fs@freebsd.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Jun 2013 16:03:40 -0000 On Jun 12, 2013, at 1:49 PM, Jeremy Chadwick wrote: > Mark, do you have any references for this? I'd love to learn/read = more > about this engineering/design aspect (I won't say flaw, I'll just say > aspect) to ZFS, as it's the first I've heard of it. I have seen that behavior with standard hard disks. Once the busy space = reached 80 % performance dropped significantly. Just deleting some old data (it is a log storage = system) performance went back to normal. Sorry I don't have graphs or anything like that. What I noticed is that = the disks were "busier" per the %busy column in gstat(8). Borja.