[linux-lvm] cmp of inactive mirrored LV fails

[starlight binnacle cx]

Hello,

Had a drive report via 'smartd' and 'smartctl'
that it was having trouble reading a sector.
For about two days "197 Current_Pending_Sector"
indicated one.  Then the drive appears to
have recovered itself and the count went
to zero.  Strangely a 'dd iflag=direct'
of the drive to /dev/null was successful
during the period where the unreadable sector
count was  non-zero.  'smartctl -l error'
reports no errors.

Concerned, I ran a 'cmp' of the two mirror
image LVs (_mimage_0 vs _mimage_1) for each
of the LVs on the drive.  Two compare
differently; in particular one that is
presently not "open" according to the 'lvs'
command failed to compare.

Does anyone know how to deal with this?
A concern is that the _mimage_0 LV is
on the drive experiencing the problem.

Versions are

lvm2-2.02.84-6.el5_7.1 
kernel-2.6.18-274.el5

Thanks