[linux-lvm] vgchange partial mount fails

[Tom Robinson <tom.robinson@oxtel.com>]

Hi,

I'm trying to do a partial mount of a VG in order to rescue data from it
(the last of the 8 PVs has died)

If I do vgchange -P -a y vg1
It says:

  Partial mode. Incomplete volume groups will be activated read-only.
  7 PV(s) found for VG vg1: expected 8
  Logical volume (lv1) contains an incomplete mapping table.
  7 PV(s) found for VG vg1: expected 8
  Logical volume (lv1) contains an incomplete mapping table.
  1 logical volume(s) in volume group "vg1" now active

Which looks like it might have worked, but in /dev/mapper I have:

crw-rw----  1 root root  10, 63 May 30 02:48 control
brw-------  1 root root 254,  0 Oct 25 13:20 vg1-lv1

But I can't mount vg1-lv1 (its ext2 - but it says "must specify fs type).

What is wrong? Have I misconfigured lvm / dm?
are there any lines I need in my config file?
Are there any tools I can run to get more info?

The array was built with LVM1 & 2.4.18,
I'm now using LVM2/DM under 2.6.11.10

Also, It looks like it has done something, because if I try
to deactivate it with "vgchange -P -a n vg1" I get:

  Partial mode. Incomplete volume groups will be activated read-only.
  7 PV(s) found for VG vg1: expected 8
  Logical volume (lv1) contains an incomplete mapping table.
  Can't deactivate volume group "vg1" with 1 open logical volume(s)

Any help greatly appreciated.
Kind regards,
 Tom