From owner-freebsd-fs@FreeBSD.ORG Tue Dec 9 06:43:58 2008 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 7BC85106564A for ; Tue, 9 Dec 2008 06:43:58 +0000 (UTC) (envelope-from andrew@modulus.org) Received: from email.octopus.com.au (email.octopus.com.au [122.100.2.232]) by mx1.freebsd.org (Postfix) with ESMTP id 3C97E8FC1A for ; Tue, 9 Dec 2008 06:43:58 +0000 (UTC) (envelope-from andrew@modulus.org) Received: by email.octopus.com.au (Postfix, from userid 1002) id F1FB9178A7; Tue, 9 Dec 2008 17:43:55 +1100 (EST) X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on email.octopus.com.au X-Spam-Level: X-Spam-Status: No, score=-1.4 required=10.0 tests=ALL_TRUSTED autolearn=failed version=3.2.3 Received: from [10.1.50.60] (ppp121-44-18-158.lns10.syd7.internode.on.net [121.44.18.158]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: admin@email.octopus.com.au) by email.octopus.com.au (Postfix) with ESMTP id F0DEF1732D; Tue, 9 Dec 2008 17:43:48 +1100 (EST) Message-ID: <493E12EC.4050801@modulus.org> Date: Tue, 09 Dec 2008 17:40:44 +1100 From: Andrew Snow User-Agent: Thunderbird 2.0.0.14 (X11/20080523) MIME-Version: 1.0 To: Bryan Alves , freebsd-fs@freebsd.org References: <92f477740812082155y3365bec7v5574206dd1a98e26@mail.gmail.com> In-Reply-To: <92f477740812082155y3365bec7v5574206dd1a98e26@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Subject: Re: ZFS resize disk vdev X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Dec 2008 06:43:58 -0000 Bryan Alves wrote: > I'm thinking about using a hardware raid array with ZFS, using a single disk > vdev zpool. I want the ability to add/remove disks to an array, and I'm > still unsure of the stability of zfs as a whole. I'm looking for an easy > way to resize and manage disks that are greater than 2 terabytes. > If I have a single block device, /dev/da0, on my system that is represented > by a zfs disk vdev, and the size of this block device grows (because the > underlying hardware raid expands), will zfs correctly expand? And will it > correctly expand in place? In theory, this works fine - I have never tried it myself. The only other way to expand a zpool is by adding more vdevs: You cannot change a vdev once it is created other than to take it from a single disk to a mirror. Sun's ZFS best practice guide states that you should avoid a single disk vdev because performance on the whole suffers and is worse than UFS. I am going to publish some benchmark figures soon to back this up, based on testing I did with a 16 disk hardware RAID6. ZFS was *alot* faster when I gave it the disks in a RAIDZ2 vdev. - Andrew