From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kay Sievers" Subject: Re: RFC - device names and mdadm with some reference to udev. Date: Mon, 27 Oct 2008 17:37:38 +0100 Message-ID: References: <18692.62860.863118.727187@notabene.brown> <20081027082257.GB1801@piper.oerlikon.madduck.net> <1225120416.4845.128.camel@firewall.xsintricity.com> <20081027161000.GG17300@skl-net.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20081027161000.GG17300@skl-net.de> Content-Disposition: inline Sender: linux-raid-owner@vger.kernel.org To: Andre Noll Cc: Doug Ledford , martin f krafft , Neil Brown , linux-raid@vger.kernel.org, Michal Marek List-Id: linux-raid.ids On Mon, Oct 27, 2008 at 17:10, Andre Noll wrote: > On 11:13, Doug Ledford wrote: > >> > I would really like to have a clear separation of competencies. >> > Ideally, mdadm never creates any devices but leaves it all to udev, >> > and all configuration about alternate names ("symlinks") is done in >> > the udev rules file. >> >> This would then require that we have a working udev in our initrd >> images. It would greatly increase the complexity of early booting as a >> result. > > Given that the initramfs usually contains busybox, one can also using > mdev. It's much simpler than udev and it's good enough if the only > thing you want to do is mounting the root partition that resides on > a software raid array. Depends on your definition of "usual". Debian, Fedora, openSUSE, Ubuntu, Gentoo (as far as Gentoo counts as a distro with a default setup) none of them uses any busybox/mdev setup, and all use udev in initramfs. It's very simple to setup and follows the same logic as udev running in the rootfs, There is absolutely no "increase of complexity" involved if you use udev in the real root anyway, you just copy the binaries and the rules, and on bootup you wait for /dev/root to show up, mount it and start /sbin/init. Custom busybox stuff does not support any non-trivial feature a "general purpose" distro needs to support today. Kay