From owner-freebsd-current@FreeBSD.ORG  Wed Oct  9 15:10:16 2013
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@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 ESMTP id 00A9DD2D;
 Wed,  9 Oct 2013 15:10:15 +0000 (UTC)
 (envelope-from wblock@wonkity.com)
Received: from wonkity.com (wonkity.com [67.158.26.137])
 (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by mx1.freebsd.org (Postfix) with ESMTPS id A65202DC1;
 Wed,  9 Oct 2013 15:10:15 +0000 (UTC)
Received: from wonkity.com (localhost [127.0.0.1])
 by wonkity.com (8.14.7/8.14.7) with ESMTP id r99FACs7037163;
 Wed, 9 Oct 2013 09:10:12 -0600 (MDT)
 (envelope-from wblock@wonkity.com)
Received: from localhost (wblock@localhost)
 by wonkity.com (8.14.7/8.14.7/Submit) with ESMTP id r99FACBZ037160;
 Wed, 9 Oct 2013 09:10:12 -0600 (MDT)
 (envelope-from wblock@wonkity.com)
Date: Wed, 9 Oct 2013 09:10:12 -0600 (MDT)
From: Warren Block <wblock@wonkity.com>
To: Freddie Cash <fjwcash@gmail.com>
Subject: Re: [CFT] Patch to bsdinstall to support root-on-ZFS and GELI
In-Reply-To: <CAOjFWZ4BMMna25KnD7RgRiLr5dszjrT9AdGjJi5XQXB9q1=Tmw@mail.gmail.com>
Message-ID: <alpine.BSF.2.00.1310090908480.37118@wonkity.com>
References: <52531295.7090700@allanjude.com> <52546844.2010608@freebsd.org>
 <CAOjFWZ4BMMna25KnD7RgRiLr5dszjrT9AdGjJi5XQXB9q1=Tmw@mail.gmail.com>
User-Agent: Alpine 2.00 (BSF 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3
 (wonkity.com [127.0.0.1]); Wed, 09 Oct 2013 09:10:12 -0600 (MDT)
Cc: FreeBSD-Current <freebsd-current@freebsd.org>,
 Nathan Whitehorn <nwhitehorn@freebsd.org>
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
 <freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-current>, 
 <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
 <mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 09 Oct 2013 15:10:16 -0000

On Tue, 8 Oct 2013, Freddie Cash wrote:

> On Tue, Oct 8, 2013 at 1:17 PM, Nathan Whitehorn <nwhitehorn@freebsd.org>wrote:
>
>> 4. What is this gnop stuff for?
>>
>
> Can't comment on the rest, but gnop is required to create 4K-aligned vdevs
> where the minimum block size is 4K (aka ashift=12).

Right, but to emphasize: the gnop hack forces ZFS to 4K blocks.  It does 
not, by itself, guarantee alignment with 4K native blocks on the drive, 
that has to be done by making the partitions aligned.