From owner-freebsd-current@FreeBSD.ORG  Tue Dec 20 04:10:17 2011
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: freebsd-current@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id E71B21065675;
	Tue, 20 Dec 2011 04:10:17 +0000 (UTC)
	(envelope-from wblock@wonkity.com)
Received: from wonkity.com (wonkity.com [67.158.26.137])
	by mx1.freebsd.org (Postfix) with ESMTP id A247C8FC15;
	Tue, 20 Dec 2011 04:10:17 +0000 (UTC)
Received: from wonkity.com (localhost [127.0.0.1])
	by wonkity.com (8.14.5/8.14.5) with ESMTP id pBK4AG4h002046;
	Mon, 19 Dec 2011 21:10:16 -0700 (MST)
	(envelope-from wblock@wonkity.com)
Received: from localhost (wblock@localhost)
	by wonkity.com (8.14.5/8.14.5/Submit) with ESMTP id pBK4AGO8002043;
	Mon, 19 Dec 2011 21:10:16 -0700 (MST)
	(envelope-from wblock@wonkity.com)
Date: Mon, 19 Dec 2011 21:10:16 -0700 (MST)
From: Warren Block <wblock@wonkity.com>
To: Alexander Best <arundel@freebsd.org>
In-Reply-To: <20111219225633.GA77147@freebsd.org>
Message-ID: <alpine.BSF.2.00.1112192022160.1741@wonkity.com>
References: <20111219224700.GA75581@freebsd.org>
	<32197.1324334968@critter.freebsd.dk>
	<20111219225633.GA77147@freebsd.org>
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-4.2.7
	(wonkity.com [127.0.0.1]); Mon, 19 Dec 2011 21:10:16 -0700 (MST)
Cc: freebsd-fs@freebsd.org, Poul-Henning Kamp <phk@phk.freebsd.dk>,
	freebsd-current@freebsd.org
Subject: Re: can a wrong alignment cause a decrease in a hdd's life
 expectancy?
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
	<freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/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: Tue, 20 Dec 2011 04:10:18 -0000

On Mon, 19 Dec 2011, Alexander Best wrote:

> no problem. so will the improper alignment also not cause a life expectancy
> shortage in case of a hdd (non-flash-based)?
>
> and one other question: the hdd also supports usb 3. will the improper
> alignment have any effect (speed wise) when connected via usb 3, or is even
> usb 3 too slow to notice the performance drop due to the improper alignment?

Many variables: file system, file size, drive firmware...  The only 
reason not to fix it is time.  And space for a temporary copy... two, 
two reasons not to fix it.

Benchmark it as-is, back up, realign, restore, benchmark again.

Or live with the gnawing, creeping doubt of not knowing for sure. 
Every day wondering "is that drive slower than it could be just from a 
simple alignment error?  Is every read a mere fraction of its 
potential?

But it's probably fine.  No pressure.