From owner-freebsd-fs@FreeBSD.ORG Mon Jun 22 23:04:58 2015 Return-Path: Delivered-To: freebsd-fs@nevdull.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 3FE845AB for ; Mon, 22 Jun 2015 23:04:58 +0000 (UTC) (envelope-from delphij@delphij.net) Received: from anubis.delphij.net (anubis.delphij.net [64.62.153.212]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "anubis.delphij.net", Issuer "StartCom Class 1 Primary Intermediate Server CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 26B2B132 for ; Mon, 22 Jun 2015 23:04:57 +0000 (UTC) (envelope-from delphij@delphij.net) Received: from zeta.ixsystems.com (c-71-202-112-39.hsd1.ca.comcast.net [71.202.112.39]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by anubis.delphij.net (Postfix) with ESMTPSA id 522071839B; Mon, 22 Jun 2015 16:04:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=delphij.net; s=anubis; t=1435014297; x=1435028697; bh=CwINWeWEfXWL5C6yjw1YlEYPjk/+4gqrCFXiwHzrN88=; h=Date:From:Reply-To:To:CC:Subject:References:In-Reply-To; b=U4hdbUqBJjwrvgsKB5jFDJzTqHxpcOvktenTbDAiFN8C4nWvapL4oR2vlUc59DZtt kq2HrrHWIlhVN7IMKKahMqHBOrtAlysP96Kf7kSpGuG9p8vb4L0hNlUb08UZV6LTi2 FpgD0PNGTsFfC/JqWEB/j+46e2ipvymCpNQE1eOY= Message-ID: <55889498.3090405@delphij.net> Date: Mon, 22 Jun 2015 16:04:56 -0700 From: Xin Li Reply-To: d@delphij.net Organization: The FreeBSD Project MIME-Version: 1.0 To: kpneal@pobox.com, Quartz CC: FreeBSD FS Subject: Re: ZFS raid write performance? References: <5587C3FF.9070407@sneakertech.com> <20150622121343.GB60684@neutralgood.org> In-Reply-To: <20150622121343.GB60684@neutralgood.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit 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: Mon, 22 Jun 2015 23:04:58 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 06/22/15 05:13, kpneal@pobox.com wrote: > For both reads and writes all levels of raidz* perform slightly > faster than the speed of a single drive. _Slightly_ faster, like, > the speed of a single drive * 1.1 or so roughly speaking. How big is the data block for each read-write? For large blocks RAID-Z is likely to perform nearly as well as stripped disks (e.g. 3 disks RAID-Z is slightly slower than 2 disk stripped, but would be much better than single disk pool). Typically copying data would use larger data blocks. For smaller writes it's likely to have worse results. > Finally, single GigE is _slow_. I see no point in a "landing pad" > when using unbonded GigE. How will a "landing pad" help when let's say we have 10GigE or even faster network connection? Cheers, - -- Xin LI https://www.delphij.net/ FreeBSD - The Power to Serve! Live free or die -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.5 (FreeBSD) iQIcBAEBCgAGBQJViJSYAAoJEJW2GBstM+nsVR0QAILGeNt4iT+mT1NeEEBiFtng wcdmzNHeUueSjRl/ecJl4O6UbDH/OAxrUwLTyj6/mP8J60JhfIZisrcnSYXCSYQL 6INTAFy8u+eD7ewMNYXr0PddDku3bsTKSC7zlSZKURctlkqX1gEatGLJDDhDMqJj KCcGpBnNX5CFS9y6UrCxbezoPwYlGf1CrEQooin5s5bLKWBwjBnG+XsaURtCOvXo aY6ctTHyKDhuDWfBlaSU73eaFAw6zjcjVvJh6BHVA3JZSwx5F4vFT9ahjpPSimvS h2byxrtSEi6PAIF+f7T+4zRoCqy+i2yYmnZlqHRQtGBtipF1cnzFlGQsGQtussE/ mamcXhcZDm2HbmxLyoUV15vNG4m/zvgMJK6VpMJrdbO5u/DfCDer/zuJyWJt6N/B Ytldb/a24WLpKEDtdUtkFw774GPOgXk8YEU/TN6lyxRx5Ua6wb8kB66npEZi3eMN tvdD45gKKVXmB5ooQjAiRzuOanKhDR40OBpCD1ZgNl513mSGJ0iNeJVGMzz2gakj 2r1GcRi+5DZTfcupc2NOLwe+8JM5B0QQzXCmuHS/eTdTGBBR4tfyIX8D5uxZs3wq 2CHPRg3yQxy0JOk14+q6g1uJfdiBjBt1SKF+gFD0TMuIFGEnREx6DpcNrJp3uPMF INYxVG0U2UUmTYIeM2iJ =CIqL -----END PGP SIGNATURE-----