I would not expect them to be the same.  physical_mb (and I always get this
confused and have to look it up...) is the space occupied, including any
"dead" space inside aggregates.  logical_mb is the space occupied, not
including any "dead space" inside aggregates.

When a file is expired, if it is a small file living inside an aggregate on
a tape, the logical_mb count will drop, but the physical_mb count will not.
The physical_mb count will drop later when the tape is reclaimed; reclaim
squishes out the dead space inside aggregates as it goes.

Since your onsite and offsite pools have tapes that are not exact image
copies of each other, and the tapes reclaim at different rates/different
times, they should be somewhat different.  (Now if they're off by
terrabytes, I would worry...)
See if adding sum(logical_mb) to the query doesn't give you closer numbers.


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Wanda Prather
The Johns Hopkins Applied Physics Lab
443-778-8769
wanda_prather AT jhuapl DOT edu

"Intelligence has much less practical application than you'd think" -
Scott Adams/Dilbert
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