From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay2.corp.sgi.com [137.38.102.29]) by oss.sgi.com (Postfix) with ESMTP id 57A897F3F for ; Mon, 18 Mar 2013 15:39:39 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay2.corp.sgi.com (Postfix) with ESMTP id 34BB1304048 for ; Mon, 18 Mar 2013 13:39:35 -0700 (PDT) Received: from mail.lichtvoll.de (mondschein.lichtvoll.de [194.150.191.11]) by cuda.sgi.com with ESMTP id Ko5DM13U0WPXzKkj for ; Mon, 18 Mar 2013 13:39:34 -0700 (PDT) From: Martin Steigerwald Subject: Re: Xfs_repair and journalling Date: Mon, 18 Mar 2013 21:37:40 +0100 References: <51455408.4070801@hardwarefreak.com> (sfid-20130317_104906_951045_BA368DB9) In-Reply-To: <51455408.4070801@hardwarefreak.com> MIME-Version: 1.0 Message-Id: <201303182137.41344.Martin@lichtvoll.de> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com, stan@hardwarefreak.com Cc: Subranshu Patel Am Sonntag, 17. M=E4rz 2013 schrieb Stan Hoeppner: > On 3/16/2013 10:56 AM, Subranshu Patel wrote: > > This is not observed in EXT4, fsck successfully recovers without > > mounting the filesystem. > = > And this is the real problem. You're *assuming* XFS should behave in > the same manner as EXT4. Why would you assume a Ferrari should behave > like a Tata Nano? > = > XFS is far more sophisticated than EXT4 in many, many ways, including > recovery after unclean shutdown. XFS kernel code performs journal > playback/recovery automatically when the filesystem is mounted. > xfs_repair is a tool for fixing filesystems that are broken, not simply > in need of journal playback. Thus xfs_repair has no code to perform > journal recovery. > = > EXT4 (and EXT3) lacks this sophistication and must call a user space > tool, e2fsck, to perform journal playback/recovery. Stan, to all what I know this is just not true. Ext4 and Ext3 are perfectly capable to replay their journals as well. I = would have notices with various Ext4 installations on laptops and = workstations that had a unclean shutdown way more often than the two unclea= n = shutdowns you mentioned. My previous main laptop a ThinkPad T42 would have = been broken by every month or so, considering me playing around and managin= g = to crash it every once in a while. Thats the whole point of being a journaling filesystem. > XFS is the Ferrari of Linux filesystems and EXT is the Tata. Keep that > in mind as you discover many of the other differences in the future. XFS may be more advanced in many areas - for example the capacity it can = hold and the scalability to really huge setups -, but the basic ability to = replay a journal is not one of this areas. Maybe both filesystem differ under what circumstances they are still able t= o = replay their journal, but from what I gathered the fully block based journa= l = of Ext filesystem is quite robust. Additionally also BTRFS meanwhile recovers just fine from an unclean = shutdown. At least it did on the last dozen hard crashes due to BTRFS not = being able to deal nicely with out of memory situations in combination with = some form of a memleak with Planeshift and/or Intel gfx driver unless I = tweak the VM subsystem settings a bit. Also ReiserFS 3 is able to replay a journal. It was the first Linux = filesystem that had journaling. Not that I would use it but thats for other = reasons. (Yes, I did not look it up, but I think XFS did journaling by that = time or even earlier on IRIX already.) And with all the mentioned filesystem, I would always first mount after a = unclean shutdown and expect that all is fine. Just if it isn=B4t I would = consider other options like repair tools. The XFS tools may the tools suite = that guides to this behaviour more than tools for other filesystems however. Thanks, -- = Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs