From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: EXT4 Larger Than 16TB Date: Mon, 8 Jul 2013 22:14:03 -0400 Message-ID: <20130709021403.GC6000@thunk.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Michael Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:36052 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751441Ab3GICOG (ORCPT ); Mon, 8 Jul 2013 22:14:06 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Jul 08, 2013 at 04:32:50PM -0500, Michael wrote: > I have a currently 15TB FS that I want to expand to 18TB. > Unfortunately EXT4 e2fsprogs has an issue that stops you from being > able to do this: > > sudo resize2fs /dev/md0 > resize2fs 1.42.5 (29-Jul-2012) > resize2fs: New size too large to be expressed in 32 bits > > It seems to me, reading the change logs, that this only supported if > you created your FS with 64 bit specified. There seems to have been a > patch last year that added support for changing 32->64bit, but I had a > hard time finding/tracking that. Unfortuantely, there is no patch that would enable this. In theory it could be done; it would require doubling the size of the block group descriptors, which would require moving other metadata blocks out of the way. Resize2fs does do this when growing a file system off-line when no blocks are available from the resize inode, but no one has implemented the necessary changes to extend this to adding the 64-bit feature. So it's technically possible, but it's not implemented at this time. Sorry, - Ted