Now, that I really understand how it worked and how to use it, I really enjoy volume manager. Anyone has to use it !!
Here is some tricks and tips to use volume with LVM 2.
Once I got an error using either a vg or lv command, I got this :
Incorrect metadata area header checksum
It's was only because LVM was checking my boot partition ( /boot ) , and as it isn't a part of a volume group, it gives the error.
So, what you have to do, is to simply tell to LVM to not scan the partition.
As my boot partition was :
I edit this file :
and change this line :
filter = [ "r|/dev/cdrom|" ]
and add my partiton, so it changed to :
filter = [ "r|/dev/cdrom|","r|/dev/hda1|" ]
And then do:
to let the volume manager known about the changes, and you won't see anymore the error. If you see still, you probably have an other device that doesn't need to be scan, like a cd rom or any other device. So, add it to the last file mentioned.