>> On Wed, 19 Nov 2008 11:37:19 -0500, Thomas Denier <Thomas.Denier AT 
>> JEFFERSONHOSPITAL DOT ORG> said:

> The reclamation you describe still creates a volume with 100% of
> its capacity available for future writes,

Future, exactly.  Certainly not "right now".  I have reusedelay at
somewhere about 5.

> at the cost of writing off the 30% of the volume that was available
> for future writes and using 10% of another volume to relocate the
> contents. This results in the same net gain of 60% of a volume
> available for future writes with only a quarter of the amount of
> data movement.  I don't see why you find this objectionable.

I don't like wasting tape drive time to convert 'one 30% full volume,
one empty scratch' to 'one 5% full volume, one PENDING and unavailable
for a week'.  Reclamation is (should be) about servicing the next
write request, not some abstract.

Worse is when reclamation like this breaks collocation; I've had this
happen several times.  Luckily, I've never been run totally out of
'filling' tapes by this quirk.

It's possible you've never had sufficiently tight resources to
appreciate the PENDING implications of moving data; unfortunately,
I've spent several months-long periods that tightly constrained.


On the other hand, I'm well known for pedantry. :)


- Allen S. Rout