[linux-lvm] Unable to mount snapshot

[John Craig <johncraig01@netscape.net>]

Hi,

I successfully created a snapshot of an active LV with XFS filesystem, 
and ldisplay shows it to be operating correctly. However, when I try to 
mount the snapshot, it says "wrong fs type, bad option, bad superblock 
on /dev/system/snap or too many mounted file systems"

Can anyone help, or shed some light on why this is happening? Is there a 
workaround?

The mount command was "mount -t xfs -o ro /dev/system/snap /mnt/snap"

I am running SuSE 9.0 on x86-64, with kernel 2.4.21-149, lvm version 
1.0.7(mp-v6). I have a volume group running on 3 raid arrays, each 0.9 
TB, for a total of 2.7 TB. It has 2 active LVs, one of them 2 TB, and 
the other 500GB, leaving about 249GB unallocated. I created the snapshot 
with:

lvcreate -L 200G -s -n snap /dev/system/adsdata

As I said, the snapshot seems to be working correctly, but when I bring 
up the LVM tool in YAST, it shows the original LV, with capacity 1.9 TB, 
mounted, and the snapshot  with a capacity of 1.9TB, unmounted. When I 
try to set the mount point for the snapshot, it says the capacity is 
wrong, it needs to be <= 249GB. In other words, it seems to be treating 
it as if it were a regular LV, not a snapshot..

The listing of lvdisplay is:
--- Logical volume ---
LV Name                /dev/system/snap
VG Name                system
LV Write Access        read only
LV snapshot status     active destination for /dev/system/adsdata
LV Status              available
LV #                   3
# open                 0
LV Size                2 TB
Current LE             16383
Allocated LE           16383
snapshot chunk size    64 KB
Allocated to snapshot  16.66% [33.29 GB/199.90 GB]
Allocated to COW-table 100 MB
Allocation             next free
Read ahead sectors     1024
Block device           58:2