From owner-freebsd-questions@FreeBSD.ORG Wed Feb 19 05:25:30 2014 Return-Path: Delivered-To: questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 50E4625C for ; Wed, 19 Feb 2014 05:25:30 +0000 (UTC) Received: from mail-yk0-x22c.google.com (mail-yk0-x22c.google.com [IPv6:2607:f8b0:4002:c07::22c]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 0546519BD for ; Wed, 19 Feb 2014 05:25:29 +0000 (UTC) Received: by mail-yk0-f172.google.com with SMTP id 200so36084279ykr.3 for ; Tue, 18 Feb 2014 21:25:29 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=content-type:mime-version:subject:from:in-reply-to:date:cc :message-id:references:to; bh=K6ZpUEIl19jderG+0rBq/n9eC9SeapDoSLPIsi+LNIM=; b=xbjiWfj+9VOO7MQ7yDVA1NXMjujJB9gpoyTDd6CIfpfcXtH71stiItkJN++uW4XcL9 NXKAfI6TAWJpofc9JDqiNoeHaIetscI3ZLIvxiBt3YEMKFbIpLKQ89/4JqvqsgROV5iB DKDBP4Jf+c44wNguKmoCE0PGB0KoDBC25L8nCSUXWjCtOwsc+9OA1hQz2O1L7Zct0jIm rpxgsdsT2Bt/BZby8L1/EjuHfjJu3eLK1CkPuJ4dZhCJbth0TxP2bpYqn+bNqEponWJZ zkRFsDC72OIEkAbBY1qqDc3mCGQzdF/T6KlSz5N0qrwOmfUZYNZDENFvMcchQlLPdkIN gPrQ== X-Received: by 10.236.35.17 with SMTP id t17mr2301898yha.138.1392787529173; Tue, 18 Feb 2014 21:25:29 -0800 (PST) Received: from [192.168.1.76] (75-63-29-182.lightspeed.irvnca.sbcglobal.net. [75.63.29.182]) by mx.google.com with ESMTPSA id 57sm66455114yhl.4.2014.02.18.21.25.28 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Tue, 18 Feb 2014 21:25:28 -0800 (PST) Mime-Version: 1.0 (Mac OS X Mail 7.1 \(1827\)) Subject: Re: ZFS on Hardware RAID controller From: aurfalien In-Reply-To: Date: Tue, 18 Feb 2014 21:25:26 -0800 Message-Id: <77EB3C34-7CBF-460C-9173-F5CE3A96EAA6@gmail.com> References: To: freebsd@fongaboo.com X-Mailer: Apple Mail (2.1827) Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.17 Cc: questions@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Feb 2014 05:25:30 -0000 Well, I think the best thing is to config a ZFS server for yourself. Its one thing to read about it, but another to do it and you would most = certainly be in a better position to sell ZFS once you know how it works = through practice. The web is rich with ZFS info. I=92m speaking for personal experience. - aurf "Janitorial Services" On Feb 18, 2014, at 7:58 PM, freebsd@fongaboo.com wrote: >=20 > I was speaking to someone else about this today, and it eventually = became apparent that we were getting into a sort-of = Abbott-and-Costello-Who's-on-First confusion... because apparently = people can mean different things when they use the term 'JBOD'. >=20 > What I have always meant when I say 'JBOD' is a (not really) RAID mode = that simply concatenates the drives into one volume in a serial fashion, = ie. 'spanning'. Most RAID controllers and RAID-enabled NAS units that I = have interacted with in my life have offered this mode and referred to = it as 'JBOD'. >=20 > In this kind of mode, the motherboard and the OS still thinks it sees = only a single volume. So now I am gathering that this is also not ideal = for ZFS, since it would still not be aware of multiple physical volumes = and be unable to optimize accordingly. >=20 > I'm learning for the first time that sometimes 'JBOD' can also refer = to each individual drive being mounted separately at least as far as the = controller and the motherboard is concerned. >=20 > I just want to confirm 100% that this is how you are recommending = multiple drives be configured for ZFS. Because when I started the thread = I was thinking of JBOD as 'spanning'. >=20 >=20 > FONG >=20 >=20 >=20 > On Tue, 18 Feb 2014, Eitan Adler wrote: >=20 >> On Tue, Feb 18, 2014 at 5:27 PM, wrote: >>>=20 >>> When we spoke, you noted that when installing ZFS on multiple disks >>> connected to a hardware RAID controller, it is best to config it to = JBOD. >>=20 >> There are a few reasons for this. >> (a) Hardware RAID serves as a single point of failure: if the >> contoller dies you have neither disk >> (b) As Andrew noted , using hardware RAID means that ZFS won't be = able >> to tell which disk is which. The ZFS management tools won't work as >> expected (they will show only one disk). >> (c) Since ZFS implements RAID itself it can use knowledge about the >> physical disks for better performance >>=20 >> Also see: https://en.wikipedia.org/wiki/ZFS#ZFS_and_hardware_RAID >>=20 >>> I tried to explain this to a colleague, but they were skeptical. = Would you >>> (or anyone) be willing to give me a one or two line sales-pitch on >>=20 >> "ZFS does RAID better than the controller." >>=20 >>> why one >>> should abandon traditional notions of RAID performance in favor of = allowing >>> ZFS to do disk management? >>=20 >> The goal isn't to give up on RAID but move its implementation to ZFS. >>=20 >> --=20 >> Eitan Adler >> Source, Ports, Doc committer >> Bugmeister, Ports Security teams >> _______________________________________________ >> freebsd-questions@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-questions >> To unsubscribe, send any mail to = "freebsd-questions-unsubscribe@freebsd.org" >>=20 > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to = "freebsd-questions-unsubscribe@freebsd.org"