New 64-bit Fedora Will Not Mount Similar 32-bit Filesystem

[Gordon Messmer]

Given the output you've shared of pvs and other LVM tools, it sort of 
looks like your older drive's LVM is in some way broken.

If I were you, I'd start by rebooting the system with the old drive 
disconnected.  This should help ensure that nothing is in an odd state 
due to running more or less random LVM commands.

I'm mostly assuming that you're using an external connection.  If not, 
don't worry about connecting and disconnecting the drive.

Before you connect the drive, open a terminal and run "tail -f 
/var/log/messages" as the root user.  The information printed as you run 
commands may be useful.

Next, connect the hard drive to the system.  The messages file should 
indicate that the drive was detected and the device name assigned to it.

Use "pvck" to see if there's anything wrong with the LVM partition. 
This LVM partition on a USB-attached hard drive is fine:
[root at vagabond ~]# pvck /dev/sdb2
   Found label on /dev/sdb2, sector 1, type=LVM2 001
   Found text metadata area: offset=4096, size=1044480

On a Fedora system, if the partition is not damaged, it'll be detected 
but not activated automatically.  At this point, you should see it in 
the volume group list (trimmed for brevity):
[root at vagabond ~]# vgdisplay
   --- Volume group ---
   VG Name               vg_vagabond
   VG Size               283.41 GiB
   VG UUID               B78GaD-Sr7W-qiVD-Yyj9-HUh2-R2KN-BSziek

   --- Volume group ---
   VG Name               vg_vagabond
   VG Size               118.22 GiB
   VG UUID               MswsDc-uBqi-U7cU-uF3T-lNtP-H9fx-aY2Enb

I now have two groups attached with the same name, which is problematic. 
  There isn't an indication of which physical volume is part of each 
volume group (I'm not sure where such information might be available), 
but I can definitely tell which volume is on my external disk based on 
the size of the group.  I'd want to rename the group on the external 
drive in order to use it on this system:
[root at vagabond ~]# vgrename B78GaD-Sr7W-qiVD-Yyj9-HUh2-R2KN-BSziek 
vg_vagabond_old
   Volume group "vg_vagabond" successfully renamed to "vg_vagabond_old"

Note that renaming the group will probably make that hard drive 
unbootable, since its configuration no longer matches the volume group's 
name.

Now that the group has a unique name, it is safe to activate it.  The 
activation process creates the device files needed to interact with the 
volume group and logical volumes.
[root at vagabond ~]# vgchange -a y vg_vagabond_old
   3 logical volume(s) in volume group "vg_vagabond_old" now active

[root at vagabond ~]# ls /dev/mapper/
vg_vagabond_old-lv_root vg_vagabond_old-lv_home  vg_vagabond_old-lv_swap

[root at vagabond ~]# ls /dev/vg_vagabond_old/
lv_home  lv_root  lv_swap

You can mount either of those device nodes to access the files they contain:
# mount /dev/vg_vagabond_old-lv_home /mnt

When you're done:
[root at vagabond ~]# umount /mnt
[root at vagabond ~]# vgchange -a n vg_vagabond_old
   0 logical volume(s) in volume group "vg_vagabond_old" now active
[root at vagabond ~]# eject /dev/sdb