From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: How to handle >16TB devices on 32 bit hosts ?? Date: Wed, 29 Jul 2009 17:07:16 +0200 Message-ID: <20090729150716.GG1534@ucw.cz> References: <19041.4714.686158.130252@notabene.brown> <20090718043155.GI4231@webber.adilger.int> <871voewm6y.fsf@basil.nowhere.org> <20090718065213.GK4231@webber.adilger.int> <20090718074811.GA2682@basil.fritz.box> <20090718134946.GA25546@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20090718134946.GA25546@mit.edu> Sender: linux-fsdevel-owner@vger.kernel.org To: Theodore Tso , Andi Kleen , Andreas Dilger , device-mapper development , Neil Brown , linux-fs List-Id: dm-devel.ids Hi! > > > Also, for filesystems like btrfs or ZFS the checking can be done > > > online and incrementally without storing a full representation of > > > the state in memory. > > > > You could, but I suspect it would be cheaper to just use a > > 64bit system than to rewrite fsck. 64bit is available > > for a lot of embedded setups these days too. > > We don't have to rewrite fsck; most of the framework for supporting an > run-length-conding for compressed bitmaps is already in patches that > add > 32-bit block numbers to e2fsprogs; we've just been more focused > on getting 64-bit block numbers support merged than implementing > compressed bitmaps, but it's only one file that would need to be > added, and we might be able to steal the compressed bitmap support > from xfsprogs --- which does this already. Well... 'If allocation pattern is bad your fsck runs out of address space and breaks on your 15T fs' would scare me. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754166AbZG2PHZ (ORCPT ); Wed, 29 Jul 2009 11:07:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751494AbZG2PHY (ORCPT ); Wed, 29 Jul 2009 11:07:24 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:54150 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750983AbZG2PHX (ORCPT ); Wed, 29 Jul 2009 11:07:23 -0400 Date: Wed, 29 Jul 2009 17:07:16 +0200 From: Pavel Machek To: Theodore Tso , Andi Kleen , Andreas Dilger , device-mapper development , Neil Brown , linux-fsdevel@vger.kernel.org, linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: How to handle >16TB devices on 32 bit hosts ?? Message-ID: <20090729150716.GG1534@ucw.cz> References: <19041.4714.686158.130252@notabene.brown> <20090718043155.GI4231@webber.adilger.int> <871voewm6y.fsf@basil.nowhere.org> <20090718065213.GK4231@webber.adilger.int> <20090718074811.GA2682@basil.fritz.box> <20090718134946.GA25546@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090718134946.GA25546@mit.edu> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > > > Also, for filesystems like btrfs or ZFS the checking can be done > > > online and incrementally without storing a full representation of > > > the state in memory. > > > > You could, but I suspect it would be cheaper to just use a > > 64bit system than to rewrite fsck. 64bit is available > > for a lot of embedded setups these days too. > > We don't have to rewrite fsck; most of the framework for supporting an > run-length-conding for compressed bitmaps is already in patches that > add > 32-bit block numbers to e2fsprogs; we've just been more focused > on getting 64-bit block numbers support merged than implementing > compressed bitmaps, but it's only one file that would need to be > added, and we might be able to steal the compressed bitmap support > from xfsprogs --- which does this already. Well... 'If allocation pattern is bad your fsck runs out of address space and breaks on your 15T fs' would scare me. -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html