From owner-freebsd-questions@FreeBSD.ORG  Sat Jul 28 23:46:28 2012
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52])
	by hub.freebsd.org (Postfix) with ESMTP id BA58110656E9
	for <questions@freebsd.org>; Sat, 28 Jul 2012 23:46:28 +0000 (UTC)
	(envelope-from erichfreebsdlist@ovitrap.com)
Received: from alogreentechnologies.com (alogreentechnologies.com
	[67.212.224.110])
	by mx1.freebsd.org (Postfix) with ESMTP id 691188FC0A
	for <questions@freebsd.org>; Sat, 28 Jul 2012 23:46:28 +0000 (UTC)
Received: from AMD620.ovitrap.com ([49.128.188.2]) (authenticated bits=0)
	by alogreentechnologies.com (8.13.1/8.13.1) with ESMTP id
	q6SNkFcQ009410; Sat, 28 Jul 2012 17:46:22 -0600
Date: Sun, 29 Jul 2012 06:48:46 +0700
From: Erich Dollansky <erichfreebsdlist@ovitrap.com>
To: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
Message-ID: <20120729064846.3bc37892@AMD620.ovitrap.com>
In-Reply-To: <alpine.BSF.2.00.1207282016110.9859@wojtek.tensor.gdynia.pl>
References: <CAMxhPyt-gF228nX0DNrdsFVXKVx6YjZVa7obfov5vf+dtV71zw@mail.gmail.com>
	<alpine.BSF.2.00.1207281229260.6801@wojtek.tensor.gdynia.pl>
	<CAKB6gVgEyvVYaUvLkvE_AU-aViJxHAiLu6drcodLjOOBeNEYLg@mail.gmail.com>
	<CAMxhPysfghi-0ufy0OU0nonqha5mFeRacPVXM0MBDe6fqxmjUg@mail.gmail.com>
	<alpine.BSF.2.00.1207282016110.9859@wojtek.tensor.gdynia.pl>
X-Mailer: Claws Mail 3.8.0 (GTK+ 2.24.6; amd64-portbld-freebsd10.0)
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Cc: questions@freebsd.org, Vladimir Videscu <vladimir.videscu@gmail.com>
Subject: Re: FreeBSD on SSD
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 28 Jul 2012 23:46:28 -0000

Hi,

On Sat, 28 Jul 2012 20:22:11 +0200 (CEST)
Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl> wrote:

> the other thing is erasing data. You want to sell that drive and
> clear your data by
> 
> dd if=/dev/zero of=/dev/disk bs=1m
> 
> but does it clear SSD cache? i don't think so. Someone sophisticated 
> enough would perform raw read of cache chips and get cached data,
> which can actually be the most important part (things you work on
> often). _______________________________________________

You will have to read afterwards the same 8GB over and over again to
make the drive believe that you want to have these 8GB faster.

How to make sure that the data is really cached?

There is no way.

Erich