I don't understand mountpoint - LVM2-mapping
 

Since Fedora10 I have the following question and I wonder if there are others with the same 'problem' or are there people who can explain why/how it works?
This is the matter:
I use LVM2 and created a physical volume as follows:
--- Physical volume ---
PV Name /dev/sda2
VG Name VolGroup00
In this volume I created 4 logical volumes:
--- Logical volume ---
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
and so on.

In my fstab of when I type mount I see:
/dev/dm-0 on / type ext3 (rw)
/proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext3 (rw)
/dev/dm-2 on /home type ext3 (rw)
/dev/dm-1 on /var type ext3 (rw)
none on /sys/bus/usb/drivers type usbfs (rw,devgid=502,devmode=664)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
gvfs-fuse-daemon on /home/hans/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=hans)
/dev/sdb1 on /media/iOmega 1tb type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096)

As I type: lvdisplay /dev/VolGroup00/LogVol00 is see:
--- Logical volume ---
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID 3Erzk2-myjc-cb8T-90ch-EAE6-lMIA-aqVqn2
LV Write Access read/write
LV Status available
# open 1
LV Size 1,94 GB
Current LE 62
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 253:3

Here is the question (what I don't get):
Where can I retrieve the link between the given LVM-names (/dev/VolGroup00/LogVol0X) and the spontanious given names like /dev/dm-X?

My gnome LVM-manager tells me the volumes are NOT mounted at all.

Then: Grub boots ok with kernel 2.6.27.19 as it points to root=/dev/VolGroup/LogVol01, but not with 2.6.27.21, as it points to root=/dev/dm-0.
The error at booting is: unable to access resume device, could not mount filesystem /dev/root.
As I replace the mountpoint in root=/dev/VolGroup/LogVol01, the error remains except for the filesystem. Now it complains about missing /dev/dm-3 (is the swap partition).

Anyone? I'm stuck/lost...

In my mind, all the devices like /dev/dm-0 are relative to your LVs.

The daemon 'device manager' take care of your LV.

You shouldn't use these device. It is internal.

Cheers.

As today I found out it is a bug in the kernel and it is discussed in bugzilla. I don't remember the thread anymore, but it's there ;-)