From owner-freebsd-questions@FreeBSD.ORG Wed Feb 19 01:28:35 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 5DF05D32 for ; Wed, 19 Feb 2014 01:28:35 +0000 (UTC) Received: from mail-qa0-x22c.google.com (mail-qa0-x22c.google.com [IPv6:2607:f8b0:400d:c00::22c]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 13FA61C5E for ; Wed, 19 Feb 2014 01:28:35 +0000 (UTC) Received: by mail-qa0-f44.google.com with SMTP id w5so24837123qac.31 for ; Tue, 18 Feb 2014 17:28:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=eitanadler.com; s=0xdeadbeef; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc:content-type; bh=l5TVKIgjqFE5SHalAIoaOnmuq5igSB/1LxpqSa0wccM=; b=m4q1mST3zgxv3Cgcvw2Zqrg3stnH252LLg8cJKtxfDeaDzZdc4vwmnrumwUOIZt1f4 mE0K96p1zkRJs8i9C7f3krTTwU6S8S9VNhxbUIn09EB8RuCOq8cSH3RWI810LlKyA/zS pi45IygFYaeODYI4S4qIO77UJc+bnPE+r4h8I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc:content-type; bh=l5TVKIgjqFE5SHalAIoaOnmuq5igSB/1LxpqSa0wccM=; b=GQp/E0/0TEyppMiRfV3XOubSJWF+yahYHdx4asTPz1XVbgvlCYXI62I+gShmx6LMDp +cd5RH7lhNuJ3qREbOeQ5YqCP2Z6adZfqhy+hzj4qjfbFTbTvRBYl1ByRxwUiP7NoiuS delWiqqadJaXjnscSKZpdjD8pbOouoCPW2c3mX0Lq0IN+YPTg34mzgNIOo92o3/TF5Tm OJq11knHtcjI3pKW2sRTi6XqGXtvMoCrG8dWcGAjmiplCCulgqOn4SKUug7eM9L0oYrp KyX5mcwlkrbHz+ax7dSbLOcS+FZMoJg+CN61cXLCCEH9EAV8+YwwRi0Tc92lkNCZVS6B rzHA== X-Gm-Message-State: ALoCoQkk1Hc0qW+R+0GMZicaC+LsscGfg4lvmqkrHiF+3J+KqlC6BngYuEGrGMTDX+tmHT7Eo5TN X-Received: by 10.224.36.195 with SMTP id u3mr47678870qad.59.1392773314315; Tue, 18 Feb 2014 17:28:34 -0800 (PST) MIME-Version: 1.0 Sender: lists@eitanadler.com Received: by 10.96.175.169 with HTTP; Tue, 18 Feb 2014 17:28:04 -0800 (PST) In-Reply-To: References: From: Eitan Adler Date: Tue, 18 Feb 2014 20:28:04 -0500 X-Google-Sender-Auth: hbLF6vx3a33cnE4GLzaLrlJwGsM Message-ID: Subject: Re: ZFS on Hardware RAID controller To: freebsd@fongaboo.com Content-Type: text/plain; charset=UTF-8 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 01:28:35 -0000 On Tue, Feb 18, 2014 at 5:27 PM, wrote: > > 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. 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 Also see: https://en.wikipedia.org/wiki/ZFS#ZFS_and_hardware_RAID > 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 "ZFS does RAID better than the controller." > why one > should abandon traditional notions of RAID performance in favor of allowing > ZFS to do disk management? The goal isn't to give up on RAID but move its implementation to ZFS. -- Eitan Adler Source, Ports, Doc committer Bugmeister, Ports Security teams