From mboxrd@z Thu Jan 1 00:00:00 1970 From: Contact Subject: Re: Make huge files strictly contiguous (fallocate, bigalloc, e4defrag...) Date: Sun, 20 Apr 2014 16:37:54 +0200 Message-ID: <5353DBC2.5080708@ovh.fr> References: <534F39F6.2000208@ovh.fr> <20140417152457.GE18591@thunk.org> <5350205E.3030403@ovh.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Theodore Ts'o , "linux-ext4@vger.kernel.org" To: =?UTF-8?B?THVrw6HFoSBDemVybmVy?= Return-path: Received: from mo29.mail-out.ovh.net ([178.32.228.29]:58620 "EHLO mo29.mail-out.ovh.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755201AbaDTOh7 (ORCPT ); Sun, 20 Apr 2014 10:37:59 -0400 In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: Le ven. 18 avril 2014 10:45:03 CEST, Luk=C3=A1=C5=A1 Czerner a =C3=A9cr= it : > > The way you're using dd for this purpose is wrong. I > said that dd can write to the file without truncating it first, but > it's not doing it by default. You have to use 'notrunc' see man > page. But I think that it would not have made a difference anyway. > Thansk, I stand corrected. I'll try it to see whether I can get better=20 results with it. > And even though you can turn off backup superblock you > can not turn off writing group descriptors. > While we're at it, how can I do this? I searched the=20 mkfs.ext4/mke2fs.conf/ext4/tune2fs man pages for the option to turn off= =20 writing backup superblock you mentioned, however the closest I found is= =20 tune2fs -O ^sparse_super which is part of the defaults mke2fs.conf=20 options... Could you point me at it so that I can try to get this=20 source of non-contiguity away? Thanks, -Bastien -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html