> Suppose I've a storage pool called tapepool and a copy storage pool called
> disaster-recovery, both sequencial storage pools. After some data migrated
> to the tapepool storage pool a BACKUP STGPOOL is executed to copy this
> data to disaster-recovery. Some time later, new data are migrated to the
> tapepool again and I would like to know what will happen when the second
> BACKUP STGPOOL will be executed.
>
> Will TSM ask the last disaster-recovery tape volume and extend it? Or will
> TSM ask another tape scracth volume to disaster-recovery and fill it with
> only the new files that were last migrated to tapepool?

That depends on the status of the previously used tape. If that tape can
still be mounted for writing, TSM will add the new files to that tape.
If the tape cannot be mounted for writing, TSM will mount a scratch tape
and write the new files on it. The usual reason for the second situation
is that the previously used tape was sent to an offsite vault.