From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?Lo=EFc?= Minier Subject: Weird discrepancy between /dev/mapper/* and /dev/dm-* devices breaks lilo Date: Wed, 31 Jan 2007 11:47:37 +0100 Message-ID: <20070131104737.GA29370@bee.dooz.org> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids Hi, When issuing the same dmsetup commands on two device nodes with the same major/minor, the results are puzzling: bee:~# file /dev/dm-1 /dev/dm-1: block special (254/1) bee:~# file /dev/mapper/bee--sata-refuge /dev/mapper/bee--sata-refuge: block special (254/1) bee:~# dmsetup table /dev/mapper/bee--sata-refuge 0 131072 linear 8:2 117440896 bee:~# dmsetup table /dev/dm-1 dm_task_set_name: Device /dev/dm-1 not found Command failed (Same problem with short names:) bee:~# dmsetup table bee--sata-refuge 0 131072 linear 8:2 117440896 bee:~# dmsetup table dm-1 device-mapper: table ioctl failed: No such device or address Command failed This is a problem hitting lilo relatively hard as it has logic to ignore devices with the same major/minor; that is, if lilo sees "dm-1" first and then the corresponding /dev/mapper device, it will drop any reference to the mapper device. As having /boot on RAID 1 for lilo requires calling "dmsetup table" on the root device, this breaks lilo for a lot of people. Of course, it would be possible to patch lilo to explicitely skip /dev/dm-* devices, but it seems this would be a workaround instead of the real fix. This is under 2.6.18 and libdevmapper 1.02.12-1. You can find more details in Debian bug , the bug was triggered by the addition of the /dev/dm-* device in udev (see ), and affects other distributions as well, = . (RAID 1 support in lilo comes from a third-party patch added in the Debian packaging.) Bye, --=20 Lo=EFc Minier