From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from imap.thunk.org (imap.thunk.org [IPv6:2600:3c02::f03c:91ff:fe96:be03]) (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits)) (Client CN "imap.thunk.org", Issuer "CAcert Class 3 Root" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id 04B1B21F40B for ; Sat, 30 Aug 2014 18:38:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=thunk.org; s=ef5046eb; h=In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=O7as4cksyj8tjZ3aikRK9FaFUwSezlVlzlfvYfwZWss=; b=FU9ZP5kJxWT8GRdsUvNQkmlhw0rugvGP1/jvyPb+GfbSfKBamdXuDZlW7QV9wHRh3LS66HAp5g15ZSLUi8cZHemJwWACwbeW8SSFLA3m0GZjQcwyHJOAuNlKpIFIeW29en35loav4KBe3ZOti4nziFmhs6TLm5XsH4iUveELAu8=; Received: from root (helo=closure.thunk.org) by imap.thunk.org with local-esmtp (Exim 4.80) (envelope-from ) id 1XNu6I-0004kb-5N; Sun, 31 Aug 2014 01:38:38 +0000 Received: by closure.thunk.org (Postfix, from userid 15806) id 587DA580C83; Sat, 30 Aug 2014 21:38:37 -0400 (EDT) Date: Sat, 30 Aug 2014 21:38:37 -0400 From: Theodore Ts'o To: Dave Taht Message-ID: <20140831013837.GB8974@thunk.org> References: <20140830213451.GA30271@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Cc: cerowrt-devel@lists.bufferbloat.net Subject: Re: [Cerowrt-devel] Is there a particular reason cerowrt isn't using UBIFS? X-BeenThere: cerowrt-devel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Development issues regarding the cerowrt test router project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 31 Aug 2014 01:38:43 -0000 On Sat, Aug 30, 2014 at 02:57:05PM -0700, Dave Taht wrote: > I tried ubifs in the early days. It doesn't squeeze stuff down even as good > as jffs2, so the load of cerowrt exceeded 15mbyte. It does look to be an > ever more reasonable answer once you have flash sizes greater than 128mbyte. Another possible solution might be squashfs on top of ubi (instead of mtdblock). Ubi will provide the wear levelling and bad block remapping, which mtdblock doesn't do. > A thing that irks me in the age of 4G flash becoming fairly common is the > general lack of compression aside from an option to btrfs. Debian barely > fits into 2 gb It depends on what you have installed, of course. I have a debian test image which gets used for ext4 testing which is 189 megabytes uncompressed, and 57 megabytes using qcow2 compression (it gets run using qemu/kvm)[1]. It's a basic debootstrap image plus a handful of packages[2] plus xfstests (which is 22 megabytes uncompressed). [1] ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/kvm-xfstests/ [2] https://git.kernel.org/cgit/fs/ext2/xfstests-bld.git/tree/kvm-xfstests/test-appliance/packages This is still much larger than 7 megabytes in the Cerowrt's root image, granted, but it is possible to make a relatively svelte debian-based image. I've considered implementing MacOS X style compression (immutable files, compression which happens in userspace, with decompression in the kernel.) The main reason why I haven't is that for most use cases, space hasn't really been that much of an issue, or most of the files are already compressed (i.e., Java or Dalvik classpath files which are already zip compressed). It wouldn't be _that_ hard to do, but it's just not that high up on most people's priority lists. - Ted