When you use disk reclamation pool, TSM takes data off the tape, puts in
the reclamation pool.
When the RECPOOL fills to the highmig threshold, TSM will start
migration for the RECPOOL.  It will call for a filling or scratch tape
in the original pool, then move the files from RECPOOL back there.  With
only 1 drive, you obviously have to do one of these things (either
reclamation or migration) at a time.  It's the only way to do
reclamation when you only have 1 drive.

If you force the data back out by causing RECPOOL to migrate, TSM will
call for a tape mount of a FILLING or SCRATCH tape in the original pool,
and empty out the RECPOOL down to the lowmig threshold.

If you just start reclaim again, it will call for a mount of a tape in
the original pool to continue reclamation where it left off; and
continue taking data off the tape and adding to the RECPOOL.  

Just don't try to force any DELETEs,  and you can't do any harm trying
this stuff out!  TSM won't do anything that hurts your data, unless you
force it to.  The only destructive things you can do are:

DELETE VOLUME (with DISCARDDATA=YES)
DELETE FILESPACE
LABEL LIBV (with OVERWRITE=YES)
-deleting files out from under TSM at the OS level

Wanda Prather
"I/O, I/O, It's all about I/O"  -(me)