From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: patches for mdadm 1.8.0 (auto=dev and stacking of devices) Date: Sun, 23 Jan 2005 19:46:29 +0300 Message-ID: <41F3D4E5.1020300@tls.msk.ru> References: <20050123151305.GB15317@percy.comedia.it> <20050123152819.GE24350@marowsky-bree.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20050123152819.GE24350@marowsky-bree.de> Sender: linux-raid-owner@vger.kernel.org To: Lars Marowsky-Bree Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Lars Marowsky-Bree wrote: > On 2005-01-23T16:13:05, Luca Berra wrote: > >>the first one adds an auto=dev parameter >>rationale: udev does not create /dev/md* device files, so we need a way >>to create them when assembling the md device. > > Am I missing something but shouldn't this be fixed by having udev + > hotplug create the /dev entry correctly? There's a chicken-n-eggs problem here. In order for mdadm to create an md device (so it will be noticed by udev/hotplug), it have to open the control device, which, in case of md, is just any /dev/mdN. But before first array gets assembled, there's NO mdN entries in /dev. mdadm tries to open /dev/md1 to get control interface, which isn't created automatically. When an array actually gets created, it will be noticied by hotplug/udev as it should be (provided everything is set up correctly ofcourse). BTW, is there a real need to do that? In theory, one might just create the necessary /dev/md1 from within startup script... /mjt