From owner-freebsd-questions@freebsd.org Thu Aug 31 00:35:15 2017 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5BCDEE0DE06 for ; Thu, 31 Aug 2017 00:35:15 +0000 (UTC) (envelope-from wfdudley@gmail.com) Received: from mail-yw0-x22f.google.com (mail-yw0-x22f.google.com [IPv6:2607:f8b0:4002:c05::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 219831A32 for ; Thu, 31 Aug 2017 00:35:15 +0000 (UTC) (envelope-from wfdudley@gmail.com) Received: by mail-yw0-x22f.google.com with SMTP id s187so38785290ywf.2 for ; Wed, 30 Aug 2017 17:35:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=KykU1Tc9oUJERlooxwMFhmVxWjTKGUD4Gtv1uifDNF8=; b=RBga5HC/cuhHl9kt6OCPjlz0FVq5zrAXzVLdd/051Z4MLq5dzR3DNT4ilTRN8oI8Hi syqwegcpH20zUw2sSji8mBotiB4U5kbHEtYZr1nGgv5KZ0QCexZT56DhVqVyKbfiaVsI UZbr8uhEWMhs6e8z9quueklZIpgW+vFbfqPd5XJVZQdqcCezEJ2AnQAA05KT/C045wer 3egxiEA2aPTI8am+EnRQg1VRwcYB4gWRchOEJhmzvb0qLvcSo1f3KqPMCLk7xnaqQigr 3IOvnt2Dd6PxWgiao+ifloLaMM0W1OIfOrueF0BsCwAhqSzgu9pOEosOB0FYkm4tPMK8 qbkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=KykU1Tc9oUJERlooxwMFhmVxWjTKGUD4Gtv1uifDNF8=; b=qVLYCZIgDpymRxHPvgCU3hpBi9YVIDhu3u8Nk5IOLX+RGrcCywtlG1EmRzhbTgV54p qN5HPSBzYaRurg2OsZnX3eowleq7lEt2xBENgsHfSJ4VXyzBgDIY7wCDeQ9TMoM5brKQ CiObIse+6XS6r+8WxyWd8+2vF/mxLwb9iusPNXsKkVsLTBQ6AMEuIZ/znyLwwmyHacIM T8wHhFk2f6FSq4iNlV+rSNOZkE+QSdM+Umvtk81xZ7Z733r/yAxBTJkWEmzaXi9fFJhv X7KTYrHQ5E9evWjl4yPQBKnoyu8eFmOw7TO+7Xne7kRTStzhKOqWBeqWiq6JakJaNdm5 XRrQ== X-Gm-Message-State: AHYfb5h4Wvmrbb5Y62BOixeF11ulXDC+xhElPnZZOWwHmVSMqwBOe5a2 sOQYdRdph2m/0Px2X755fr3BoGHERU0y X-Received: by 10.37.43.7 with SMTP id r7mr2735444ybr.96.1504139714155; Wed, 30 Aug 2017 17:35:14 -0700 (PDT) MIME-Version: 1.0 Received: by 10.37.178.15 with HTTP; Wed, 30 Aug 2017 17:35:13 -0700 (PDT) In-Reply-To: <26f5e88e-1ea7-6332-ca5e-f055cfbdd280@fjl.co.uk> References: <26f5e88e-1ea7-6332-ca5e-f055cfbdd280@fjl.co.uk> From: William Dudley Date: Wed, 30 Aug 2017 20:35:13 -0400 Message-ID: Subject: Re: help creating new gmirror > 2TB To: Frank Leonhardt Cc: freebsd-questions Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.23 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 31 Aug 2017 00:35:15 -0000 I've never heard of AFD, and is having 4K sectors something I have control of? Or is tthat something the manufacturer controls? My drives are: 2 of Seagate 4TB IronWolf NAS SATA 6Gb/s NCQ 64MB Cache 3.5-Inch Internal Hard Drive (ST4000VN008) Which doesn't have the magic word "AFD" anywhere in the description. Also, I happen to like the idea of "fixing" the gmirror code to put it's metadata in the penultimate sector if it discovers GPT in the last sector, but I suppose I shouldn't get my hopes up. Bill Dudley On Wed, Aug 30, 2017 at 5:57 PM, Frank Leonhardt wrote: "I'm sure you'll be okay with MBR assuming it's an AFD (4K sector drive)." On 29/08/2017 21:12, William Dudley wrote: > >> Hi, >> >> I want to create a simple mirror > 2TB on a FreeBSD 10.3 system. >> >> I have 2 identical 4TB disks. >> >> The examples in freebsd handbook "geom-mirror" pages show creation of a >> 2TB >> mirror using >> MBR partitioning, and that has an upper limit of 2TB. >> > > I still get a bit worried about this, but I'm 99.9% sure you'll be okay > with MBR assuming it's an AFD (4K sector drive). The bodge/workaround > works. If it's SAS instead of SATA, all bets are off. > > Although I use ZFS a lot, I still prefer geom mirror for twin-disk > systems. I feel a lot more comfortable booting from it in the event of a > failure. ZFS has its good points, but so does UFS. > > Trying to get geom mirror to work with GPT as it stands just leads to > pain. I've taken a look at the code with a view to fixing this is no one > else does, but UFS is so un-cool in most circles and I don't fancy doing it > alone in case I zap someone's data. it doesn't look that tricky to move the > metadata somewhere else, and by checking for a GPT you can select between > the old/new block. It's unexpected interactions I'm worried about. > > I think we're safe with MBR until we pass 16Tb. > > Regards, Frank. > > > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe > @freebsd.org" >