From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-15?Q?Luk=E1=A8_Czerner?= Subject: Re: Question: errors=continue behaviour for failed external journal device Date: Mon, 28 Jul 2014 11:11:45 +0200 (CEST) Message-ID: References: <20140727000733.GV6725@thunk.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Vlad Dobrotescu , linux-ext4@vger.kernel.org To: "Theodore Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:21668 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752063AbaG1JL5 (ORCPT ); Mon, 28 Jul 2014 05:11:57 -0400 In-Reply-To: <20140727000733.GV6725@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sat, 26 Jul 2014, Theodore Ts'o wrote: > Date: Sat, 26 Jul 2014 20:07:33 -0400 > From: Theodore Ts'o > To: Vlad Dobrotescu > Cc: linux-ext4@vger.kernel.org > Subject: Re: Question: errors=continue behaviour for failed external journal > device > > On Sat, Jul 26, 2014 at 11:07:59PM +0000, Vlad Dobrotescu wrote: > > If this isn't the proper place for this question, please point me in > > the right direction. > > > > I couldn't find any description on Ext4's behaviour when mounted > > with errors=continue and external journal if the journal block device > > is unavailable at mount time (or becomes unavailable at some point). > > > > I would be using CentOS 7 (kernel 3.10.0-123.4.4.el7 x86_64) and > > (probably) full data journaling on a SSD. Can someone help? > > So there are two different questions. > > If you use errors=continue, there is the chance that the file system > inconsistencies that discovered could cause further file system > damage, which might lead to the loss or corruption of data files > written earlier. So it's not really recommended for most purposes, I very much agree with that, that's why I was quite surprised that I found out recently that this is the default. I was living in the delusion that the default was ERRORS_RO for as long as I can remember. So my question is, should we change it ? This really does not seem like a sane default. Thanks! -Lukas > unless you have some scheme where you are monitoring dmesgs and having > some strategy to deal with detected file system errors, or when the > system absolutely, positively must continue running, and this is more > important than potential data loss. > > If the journal block device is not present then the file system can't > be mounted, and if the system was uncleanly shut down you won't be > able to recover from the unclean shutdown by replaying the journal. > > If the journal block device is *gone*, it is possible to remove the > external journal block device, and then force a file system repair, > but if this happens after an unclean shutdown, you may very well lose > data. > > Cheers, > > - Ted > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >