From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bernd Schubert Date: Wed, 09 May 2007 12:17:08 +0000 Subject: removed disk && md-device Message-Id: <200705091417.09033.bs@q-leap.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-raid@vger.kernel.org, linux-hotplug-devel@lists.sourceforge.net Hi, we are presently running into a hotplug/linux-raid problem. Lets assume a hard disk entirely fails or a stupid human being pulls it out of the system. Several partitions of the very same hardisk are also part of linux-software raid. Also, /dev is managed by udev. Problem-1) When the disk fails, udev will remove it from /dev. Unfortunately this will make it impossible to remove the disk or its partitions from /dev/mdX device, since mdadm tries to read the device fail and will abort if this file is not there. Problem-2) Even though the kernel detected the device to not exist anymore, it didn't inform its md-layer about this event. The md-layer will first detect non-existent disk, if a read or write attempt to one of its raid-partitions fails. Unfortunately, if you are unluckily, it might never detect that, e.g. for raid1 devices. I think there should be several solutions to these problems. 1) Before udev removes a device file, it should run a pre-remove script, which should check if the device is listed in /proc/mdstat and if it is listed there, it should run mdadm to remove this device from the. Does udev presently support to run pre-remove scripts? 2.) As soon as the kernel detects a failed device, it should also inform the md layer. 3.) Does mdadm really need the device? Thanks, Bernd -- Bernd Schubert Q-Leap Networks GmbH ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ Linux-hotplug-devel mailing list http://linux-hotplug.sourceforge.net Linux-hotplug-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-hotplug-devel