From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: Tune2fs metadata_csum Date: Mon, 17 Dec 2012 09:37:03 -0500 Message-ID: <20121217143703.GB31563@thunk.org> References: <1355717041.99349.YahooMailNeo@web164606.mail.gq1.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "linux-ext4@vger.kernel.org" To: Anders Lind Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:38866 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752607Ab2LQOhG (ORCPT ); Mon, 17 Dec 2012 09:37:06 -0500 Content-Disposition: inline In-Reply-To: <1355717041.99349.YahooMailNeo@web164606.mail.gq1.yahoo.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun, Dec 16, 2012 at 08:04:01PM -0800, Anders Lind wrote: > > I tired to use tune2fs metadata_csum feature on my ext4 filesystem. > I got message like: > ~$ sudo tune2fs -O metadata_csum /dev/sda5 > tune2fs 1.42 (29-Nov-2011) > Setting filesystem feature 'metadata_csum' not supported. > > Is this tool supposed been used on unmounted device or it could be mounted? TYhe metadata_csum feature is in the e2fsprogs "master" branch in the e2fsprogs git tree. The feature is not part of an official e2fsprogs release yet. One of the things that I want to really check very carefully before I release e2fsprogs 1.43 is that e2fsck sanely recovers from checksum failures while it tries replaying the journal. Essentially, metadata_csum is supposed to provide better recovery from device failures (it doesn't really provide any kind of performance advantage), and I want to be 100% sure that it is **always** better when hardware-induced corruption happens before we release it. Regards, - Ted