From owner-freebsd-fs@FreeBSD.ORG Mon Jun 22 08:38:25 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 1F8AB941 for ; Mon, 22 Jun 2015 08:38:25 +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 05E111C66 for ; Mon, 22 Jun 2015 08:38:24 +0000 (UTC) (envelope-from delphij@delphij.net) Received: from Xins-MBP.home.us.delphij.net (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 510071A0B9; Mon, 22 Jun 2015 01:38:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=delphij.net; s=anubis; t=1434962304; x=1434976704; bh=Y3NEldf89aiDa/+PxsZYkArRrEneAOaFr7bHntnjBaA=; h=Date:From:To:Subject:References:In-Reply-To; b=wWg/4XlgMZs4ce/LtrISQnKuJyvV9Dz71WP7pKvbwh8rTlnxLjKhIrYrjvByXfbbl OvpvXgJEmLku9OUoWX9qO0zYnlZGHRJUFOS6nFXAJ49eiR7DCuwzyRJWvoVGUsfvUN hdbr0ot9Vk14FKTyQD318dlCDUAbEh/KXMxF01k8= Message-ID: <5587C97F.2000407@delphij.net> Date: Mon, 22 Jun 2015 01:38:23 -0700 From: Xin Li User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Quartz , FreeBSD FS Subject: Re: ZFS raid write performance? References: <5587C3FF.9070407@sneakertech.com> In-Reply-To: <5587C3FF.9070407@sneakertech.com> 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 08:38:25 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 6/22/15 01:14, Quartz wrote: > What's sequential write performance like these days for ZFS > raidzX? Someone suggested to me that I set up a single not-raid > disk to act as a fast 'landing pad' for receiving files, then move > them to the pool later in the background. Is that actually > necessary? (Assume generic sata drives, 250mb-4gb sized files, and > transfers are across a LAN using single unbonded GigE). That sounds really weird recommendation IMHO. Did "someone" explained with the reasoning/benefit of that "landing pad"? I don't have hardware for testing handy, but IIRC even with 10,000 RPM hard drives, a single hard drive won't do much beyond 100MB/s (maybe 120MB/s max) for sequential 128kB blocks, so that "landing pad" would probably not very helpful assuming you can saturate your GigE network (and keep in mind that with a file system in place it's not a perfect sequential operation; plus if there is something wrong with that hard drive you will have to start over rather than just replacing the bad drive). Cheers, -----BEGIN PGP SIGNATURE----- iQIcBAEBCgAGBQJVh8l+AAoJEJW2GBstM+nsD8EP/RHR8Oiqf6FFVG4LT+CSqXLc GIsSqaR/6/l04Ah0ixTkaubNvOELPlFZdFKQDtNd2u71G2Z7XtMbNvOK3G7whOxC 6a5xdNfdIYs7lq3jatN79BP9dygtgICsb1oMrCyAzd/tQc+cTvPabC/OxR4TtEJn ZumP6LworIDGp1ruMrmQ7VvcOKhCxzs4VO7G8Lcj/WkhzR3TDEsZuzzqefWg1RlO SBWJEwMGUugKWOCvgm8eQ2Hmw3btYbee1wfzuojtRN+d+IS8PtmsFpGBo8PCRSb8 lPz1Cf1fY4/zwruiG4EI+0CFvfr/05rN6DBRolyctdCGY1zX4rgKu6DT62kFkUR7 1nQdwxQ9slsQck1vyfAv2nIlGU530E696ZoS8/Ppqi/P8IqktYDLXKMn9+l0s+y+ EDzfvITasvwa6GRp5oxD2wagMjhvJ9iwELBLsppbjNH2i6n6k7EUSD1WGDHyQI2O irzm7ecRd5mym14Ruk0PxOAkuRrWhIdkSEHWrK1V5MZolIMw7MTf/gzNJPDIG0tZ MP4JmaOlysmHwIxoDLwAVlfuwweT3496miRbDvjzBrexkBvOVcIQdtymhZJmGe/z DoejzWQvub5CbsDVbNAVW6HBppbW2MEqby4zyzl/Ae/IzsvYKAdVTQdmICO7wqNz XWCqRSAjysOM5RDHoyXf =Newc -----END PGP SIGNATURE-----