[linux-lvm] A problem (probably conceptual) with snapshot

[Du <eduardo@minicom.com.br>]

Today I needed to install Oracle and some other things on my PC, but I
realize that it would be better to make a snapshot and then reboot Linux
with this snapshot mounted instead of root.
Ok, I did that and changed fstab to mount my snapRoot instead root,
ok...I saw with 'df' command that it worked.
And I've installed all what I wanted, some garbage too...by the way,
this snapRoot doesnt means nothing to me, just for testing. And then I
changed the fstab again to mount the root original. But after it, all
the changes I made on snapshot was made on my root LV too. And the
lvdisplay command shows something strange now, about these two LV's. The
output is:

--- Logical volume ---
  LV Name                /dev/dutcheVG/root
  VG Name                dutcheVG
  LV UUID                aAN6BH-GqW3-zhtr-KeIt-BW4m-qEyw-RypMit
  LV Write Access        read/write
  LV snapshot status     source of
                         /dev/dutcheVG/snap_root [INACTIVE]
  LV Status              available
  # open                 0
  LV Size                9.27 GB
  Current LE             2372
  Segments               1
  Allocation             inherit
  Read ahead sectors     0
  Block device           254:5

  --- Logical volume ---
  LV Name                /dev/dutcheVG/snap_root
  VG Name                dutcheVG
  LV UUID                cj2PD2-4OYX-eCzw-kG5y-r071-icK0-dq7FBr
  LV Write Access        read/write
  LV snapshot status     INACTIVE destination for /dev/dutcheVG/root
  LV Status              NOT available
  LV Size                9.27 GB
  Current LE             2372
  COW-table size         2.00 GB
  COW-table LE           512
  Snapshot chunk size    8.00 KB
  Segments               1
  Allocation             inherit
  Read ahead sectors     0


I donno what is really happening, does anybody can explain me? Plz!!

Thanks in advance