Hi Clint,

This is normal.  Our onsite tape pool shows a % migr value too (and doesn't
have a next stg pool).  Although data is not actually being migrated to a next
pool, ADSM makes the calculation as follows (from the Admin Ref. Guide):

%Migr
     Specifies an estimate of the percentage of data in the storage pool that
can be migrated. This value is used by the high and low migration  thresholds
to determine when to start and stop migration.

     For DISK devices, this value is specified as a percentage of the value for
the estimated capacity, excluding cached data but including data on  any
volumes varied offline.

     For sequential access devices, this value is specified as the percentage
of the number of sequential access volumes in the storage pool that contain at
least 1 byte of active data.

     The %UTIL value includes cached data on a volume (when cache is enabled);
the %MIGR value excludes cached data. Therefore, when cache  is enabled and
migration occurs, the %MIGR value decreases but the %UTIL value remains the
same because the migrated data is remaining on  the volume as cached data. In
this instance, the %UTIL value decreases only when the cached data expires or
when the space that cached files are using needs to be used for noncached
files.

Laura Buckley
Storage Solutions Specialists, Inc.
buckley AT storsol DOT com