From owner-freebsd-fs@FreeBSD.ORG Wed Oct 12 16:53:57 2011 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 BCE6110656D6 for ; Wed, 12 Oct 2011 16:53:57 +0000 (UTC) (envelope-from tevans.uk@googlemail.com) Received: from mail-vx0-f182.google.com (mail-vx0-f182.google.com [209.85.220.182]) by mx1.freebsd.org (Postfix) with ESMTP id 798638FC13 for ; Wed, 12 Oct 2011 16:53:57 +0000 (UTC) Received: by vcbf13 with SMTP id f13so1077308vcb.13 for ; Wed, 12 Oct 2011 09:53:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=oEYQOKrshODihZ8d4dpyY9kXvDLYiv+iufG9qP5rgbo=; b=Zo2UQzsiWNgKhn4HRFvGCL3Rxeh8lW4JEVcKcHhCimeS8M/YMC6r8YZ5brKuU7fdlO G6zYMIzfB8cKIQSSgSrI2bhfBYUa/qgmZGwB0l4UINja0RaLSBxRnfWdseMpHAX3ArMd j6z4FE9oDXW2oLDIbF+Jc5L/ZPXln7eCyOQoU= MIME-Version: 1.0 Received: by 10.52.37.44 with SMTP id v12mr24482786vdj.53.1318436913453; Wed, 12 Oct 2011 09:28:33 -0700 (PDT) Received: by 10.52.111.201 with HTTP; Wed, 12 Oct 2011 09:28:33 -0700 (PDT) In-Reply-To: <4E95AE08.7030105@lerctr.org> References: <4E95AE08.7030105@lerctr.org> Date: Wed, 12 Oct 2011 17:28:33 +0100 Message-ID: From: Tom Evans To: Larry Rosenman Content-Type: text/plain; charset=UTF-8 Cc: freebsd-fs@freebsd.org Subject: Re: AF (4096 byte sector) drives: Can you mix/match in a ZFS pool? 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: Wed, 12 Oct 2011 16:53:57 -0000 On Wed, Oct 12, 2011 at 4:11 PM, Larry Rosenman wrote: > I have a root on ZFS box with 6 drives, all 400G (except one 500G) in a > pool. > > I want to upgrade to 2T or 3T drives, but was wondering if you can mix/match > while doing the drive by drive > replacement. > > This is on 9.0-BETA3 if that matters. > > Thanks! > Hi Larry I'm in a similar position. I have a 2 x 6 x 1.5TB raidz system, configured a while ago when I wasn't aware enough of 4k sector drives, and so ZFS is configured to use 512 byte sectors (ashift=9). All of the drives in it were 512 byte sector drives, until one of them failed. At that point, I couldn't lay my hands on a large capacity drive that still used 512 byte sectors, so I replaced it with a 4k sector drive, made sure it was aligned correctly, and hoped for the best. The performance sucks (500MB/s reads -> 150MB/s reads!), but it 'works', all my data is safe. The solution is to make sure that all your vdevs, whether they are backed by disks that have 512 byte or 4k sectors, are created with 4k sectors (ashift=12). It won't negatively affect your older disks, and you won't end up in the position I am in, where I need to recreate the pool to fix the issue (and have 12TB of data with nowhere to put it!) Cheers Tom