From owner-freebsd-questions@FreeBSD.ORG  Sun Jun  7 06:53:27 2009
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 69BDB1065670
	for <questions@freebsd.org>; Sun,  7 Jun 2009 06:53:27 +0000 (UTC)
	(envelope-from wojtek@wojtek.tensor.gdynia.pl)
Received: from wojtek.tensor.gdynia.pl (wojtek.tensor.gdynia.pl
	[IPv6:2001:4070:101:2::1])
	by mx1.freebsd.org (Postfix) with ESMTP id 60C818FC17
	for <questions@freebsd.org>; Sun,  7 Jun 2009 06:53:26 +0000 (UTC)
	(envelope-from wojtek@wojtek.tensor.gdynia.pl)
Received: from wojtek.tensor.gdynia.pl (localhost [IPv6:::1])
	by wojtek.tensor.gdynia.pl (8.14.3/8.14.3) with ESMTP id n576rL9A097773;
	Sun, 7 Jun 2009 08:53:21 +0200 (CEST)
	(envelope-from wojtek@wojtek.tensor.gdynia.pl)
Received: from localhost (wojtek@localhost)
	by wojtek.tensor.gdynia.pl (8.14.3/8.14.3/Submit) with ESMTP id
	n576rKBZ097770; Sun, 7 Jun 2009 08:53:20 +0200 (CEST)
	(envelope-from wojtek@wojtek.tensor.gdynia.pl)
Date: Sun, 7 Jun 2009 08:53:19 +0200 (CEST)
From: Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
To: Sergio de Almeida Lenzi <lenzi.sergio@gmail.com>
In-Reply-To: <1244340648.8936.7.camel@localhost>
Message-ID: <alpine.BSF.2.00.0906070848390.97754@wojtek.tensor.gdynia.pl>
References: <56942.76.25.231.251.1244295367.squirrel@webmail.wcubed.net>
	<1244306366.5333.8.camel@localhost>
	<alpine.BSF.2.00.0906062312520.93574@wojtek.tensor.gdynia.pl>
	<1244340648.8936.7.camel@localhost>
User-Agent: Alpine 2.00 (BSF 1167 2008-08-23)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
Cc: freebsd-questions <questions@freebsd.org>
Subject: Re: fsck on 1.5TB drive
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: Sun, 07 Jun 2009 06:53:27 -0000

>
>
> You are right Puchar, but sometimes (2 in 100 on powerfailure) the
> filesystem
> gets corrupted (database files opened, and being extended)...  so
> when the fsck enters, the database get corrupted..

Filesystem will rather be not corrupted, but database file data.
Non-journalled UFS with softupdates guarrantes the right sequence of disk 
updates. For example it will not allocate just freed space until freeid 
inodes/blocks are not wrote back to disk.

As in your example - extended and written something, but will end unextended 
etc..

> by using zfs or journaling I never have anothter database problem....

This is sequence problem - for example you write to file A,B and C 
then it's a crash and you have file A and C written but not B.

I though that all this "famous" database systems like mysql already have 
mechanism for that. looks like not, or it should not get corrupted.