Roy,

You don't have to do the backup of the diskpool first, but why wouldn't you?
That is what you should do every day anyway.  If all the data in diskpool
has already been backed up to your copypool in your daily processing, it
will only take a few seconds and you'll have piece of mind when you hit
return on the del volume command.

Before migrating the data to tapepool, however, do an

update stg diskpool cache=no

That will purge all the cached files in the diskpool during migration so you
shouldn't have to add the discarddata=yes when you delete the diskpool
volumes.

Bill Smoldt    SSSI
STORServer, Inc.