[linux-lvm] root on lvm

[Jeffrey Layton]

On Tue, 2004-03-16 at 18:00, Rich Turner wrote:
> i am trying to mount / on a logical volume with reiserfs. my initrd
> appears to be loading all of the appropriate modules (lvm-mod, dm-mod,
> reiserfs) but i get the following error when the initrd exits and tries
> to mount /.
> 
> device-mapper: unknown block ioctl 0x5310
> sh-2021: reiserfs_read_super: can not find reiserfs on device mapper
> (254,1)
> 
> is this related to reiserfs or lvm? or my initrd?
> using:
> lvm-2.00.07
> reiserfs-3.6.9-37
> suse-9.0
> kernel-2.4.21-144-athlon
> 

You likely are hitting a problem with the device numbering for DM
devices. The kernel dynamically allocates major and minor numbers for
the DM, so booting to a different kernel can renumber your DM devices.
Have a look at the lvm2create_initrd script that's been posted on this
list several times to see how I (and others) have handled this
situation. It's also available here:

http://poochiereds.net/svn/lvm2create_initrd

-- Jeff