From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) by finch.gentoo.org (Postfix) with ESMTP id 5B1D51381F3 for ; Sun, 1 Sep 2013 04:31:23 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 1BEFDE0EA2; Sun, 1 Sep 2013 04:31:10 +0000 (UTC) Received: from mail-la0-f41.google.com (mail-la0-f41.google.com [209.85.215.41]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id DD798E0DFD for ; Sun, 1 Sep 2013 04:31:08 +0000 (UTC) Received: by mail-la0-f41.google.com with SMTP id ec20so2697763lab.0 for ; Sat, 31 Aug 2013 21:31:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type:content-transfer-encoding; bh=9LHgjoxtcvDNwZ4zSa7D+caiu1VCTaFgYzuI96BQU1Y=; b=ubOZorcMUAG2Y4TvXrlZF+id0uTKjv1bj2U7N8GcQPt6iX681wTEGhD3fNATLeLJYj 8ufJyASADD0pPLBw+gN41G73FCwOehaDPKku8kZ0UPVYF+X+1RyVIfJYYBDwQpME4twT EIKsUemEwF30dUNnGTvJWOv3BAFAmqNpdnhs17RxTk8mv853LvyDRgzrU0hfk+wXu3ve 1XgrWkRD3LPMfJ0o/dzCIJ0Fz+d9VzEoOhVGgrGn37ITxAHSMFdaOq66eYjR8aWG9kkl Ba1aIe/YeOOPfU44PA+HymmKU/oEH3pfbVxi/Fv/b9MB7G4bdtMUQRRS/femXf3xFsi8 ynig== Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 X-Received: by 10.112.72.130 with SMTP id d2mr12464lbv.40.1378009867110; Sat, 31 Aug 2013 21:31:07 -0700 (PDT) Received: by 10.114.96.2 with HTTP; Sat, 31 Aug 2013 21:31:07 -0700 (PDT) In-Reply-To: <20130901035501.GA19963@waltdnes.org> References: <20130831120831.GA25399@pacific.net.au> <5221df6c.WS8p51iIG1y/cHXy%Joerg.Schilling@fokus.fraunhofer.de> <20130901001352.GB19271@waltdnes.org> <20130901035501.GA19963@waltdnes.org> Date: Sat, 31 Aug 2013 23:31:07 -0500 Message-ID: Subject: Re: Integrated ZFS for Gentoo - WAS Re: [gentoo-user] Optional /usr merge in Gentoo From: =?UTF-8?B?Q2FuZWsgUGVsw6FleiBWYWxkw6lz?= To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: 610c824c-d8f2-4440-a54f-f49cd5bc34f1 X-Archives-Hash: b7cb7ca6894052e73b19622120292c5e On Sat, Aug 31, 2013 at 10:55 PM, Walter Dnes wrote= : >> I usally use ext4 as filesystem. >> >> # lsmod|grep ext >> ext3 100768 0 >> jbd 39586 1 ext3 >> ext2 49572 0 >> ext4 263621 1 >> crc16 1255 2 ext4,bluetooth >> mbcache 4450 3 ext2,ext3,ext4 >> jbd2 48679 1 ext4 >> >> Isn't great what an initramfs can do? > > In this case, initramfs is your root filesystem, from which you load > another fs and then transfer (pivot root?) to it. You have to build > initramfs support into the kernel, to boot an initramfs. So my argument > still stands, regardless of whether your *INITIAL* filesystem is ext4fs, > or ZFS, or initramfs, that *INITIAL* filesystem has to be built into the > kernel. Interesting perspective. Of course, support for an initramfs is not actually a file system (it's not even in the File systems section of the kernel configuration, is in General setup); it's not possible to have initramfs as a module (that would make no sense at all); and it's code that is several orders of magnitude more simpler than the one used by ext4 (or any other journal file system). But you are right that for booting with an initramfs, you need initramfs support. > Also, I really wonder what the point is in having to use > initramfs on a system where /usr is part of /. Well, since some months ago I've been running as a module almost everything that can be compiled as a module. This allows me to run a *truly* minimal kernel, and only the necessary modules autoload automatically (one big exception: binfmt_script, I compiled that into the kernel because it was not loading automatically). I can also unload some modules when not in use anymore (and this is great to debug sometimes). This also lets me to add a lot of stuff in the kernel, as long as I add them as modules, without me worrying about bloating my kernel. Only when they are needed they are loaded. I have USB speakers, but I almost never use them; no problem, they (like almost everything else) live as modules, and only are loaded (automagically, thanks to udev) when needed. And again, I can unload them when not in use. And also, it turns out that by using dracut+systemd you could boot faster than without initramfs (although I can't find the link anymore). Finally, using only modules and dracut liberates me from thinking what should it be compiled in and what not; I just put *everything* as a module, and the kernel, udev and dracut take care of loading what's necessary. Thus, my kernel (the one running in memory) is as minimal as it can be, all the time. Oh, and one more thing; by having everything as a module, if suddenly I need support for new hardware, usually I can do a quick "make menuconfig; make modules_install", and the new module can be modprobe'd into the kernel without needing a reboot. That's convenient. Regards. --=20 Canek Pel=C3=A1ez Vald=C3=A9s Posgrado en Ciencia e Ingenier=C3=ADa de la Computaci=C3=B3n Universidad Nacional Aut=C3=B3noma de M=C3=A9xico