David,

"I'll ask the obvious.  Any chance you copypool reached 100% triggering a
reclaim?"

The reclamation ran on a primary storage pool.  There is nothing *obvious*
that could have pushed ONE tape over the pool's 50% reclamation threshold
during the midnight to 1:00 am period when reclamation launched.
Reclamation ran on that one volume only.  During our maintenance cycle,
which is running now, that particular pool can reclaim as many as 30
volumes.

Thanks.

Tab