From mboxrd@z Thu Jan 1 00:00:00 1970 From: Luca Berra Subject: Re: patches for mdadm 1.8.0 (auto=dev and stacking of devices) Date: Sun, 23 Jan 2005 18:00:09 +0100 Message-ID: <20050123170009.GD15317@percy.comedia.it> References: <20050123151305.GB15317@percy.comedia.it> <20050123152819.GE24350@marowsky-bree.de> <41F3D4E5.1020300@tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Content-Disposition: inline In-Reply-To: <41F3D4E5.1020300@tls.msk.ru> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Sun, Jan 23, 2005 at 07:46:29PM +0300, Michael Tokarev wrote: >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. exactly >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). I believe the correct solution to this would be implementing a char-misc /dev/mdadm device that mdadm would use instead of the block device, like device-mapper does. Alas i have no time for this in the forseable future. >BTW, is there a real need to do that? In theory, one might just >create the necessary /dev/md1 from within startup script... I would have done it in a script if --auto was not implemented, the changes to have auto=dev are not big, mostly man page and indenting. Regards, L. -- Luca Berra -- bluca@comedia.it Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \