From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH] mke2fs: disable resize_inode feature if 64bit feature is enabled Date: Tue, 4 Mar 2014 10:19:25 -0500 Message-ID: <20140304151925.GC23106@thunk.org> References: <1372928710-10461-1-git-send-email-guaneryu@gmail.com> <20130705012128.GA11793@gmail.com> <20130707154140.GA11993@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Eryu Guan , linux-ext4@vger.kernel.org To: =?utf-8?B?THVrw6HFoQ==?= Czerner Return-path: Received: from imap.thunk.org ([74.207.234.97]:36864 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757168AbaCDPT3 (ORCPT ); Tue, 4 Mar 2014 10:19:29 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Mar 03, 2014 at 04:40:21PM +0100, Luk=C3=A1=C5=A1 Czerner wrote= : >=20 > are you going to take this in ? >=20 > > It's better to use the resize_inode for file systems that are small= er > > than 16TB, even if the 64-bit flag is enabled, since using the meta= _bg > > style resizing spreads out the block group descriptors, which > > increases the time to mount the file system. Using the resize_inod= e > > will defer the need to go to the meta_bg-style resizing until we cr= oss > > the 16TB boundary. See my comments above. If we create a file system which is say, 1T but with the 64-bit flag, we do want the resize_inode feature to be used until we cross over the 32-bit boundary, because keeping block group descriptors contiguous speeds up the mount time. If I were to accept this patch, and/or Red Hat were to ship with it, I will predict that you will get angry customer support calls about file system mount times getting slow after doing a resize. At some point what we may want to lazily load the block group descriptors at mount time, to mitigate the slow mount time issue when using meta_bg. We have a lot of assumptions in the code that the block group descriptors are always available, though. - Ted -- 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