Gen 3 Storwize V7000 shows theoretical maximum capacity, instead of real one

product_id 10140648
FRU_part_number 01YM583
These Flashcore modules installed in Gen 3 Storwize v7000 units show 3 kinds of capacity figures:
- Capacity: This figure shows a fixed 20 TB value, which is a theoretical value, that CAN be achieved through extremely favourable compression conditions.
- Phyiscal capacity: The actual physical capacity of the modules (8.73 TB)
- Effective used capacity: The currently usable capacity after compression.

The storage uses the "Capacity" figure for all calculations: pool capacities, mdisk capacities. Both TPC (SC) and SVC's receive this figure as well.
This poses a significant risk of overallocation, since this figure is NOT valid. This is a theoretical value, that CAN be achieved, but very rarely possible with production usage. The actual capacity we can use is MUCH lower than 20TB/module, usually around 12TB.

The fact the storage reports this theoretical value, instead of actual values, almost caused a massive outage, as our Storage Administrators spotted this defect shortly before our pools would have hit 100%.

This method of capacity display contradicts IBM's "Hard to do harm" principle.

We'd need some kind of fix, so the storage displays a realistic value, instead of this highly misleading one.

I've opened PMR 40375,025,72 for this case, which was closed, saying it's a marketing decision from IBM's side, and I should open a complaint ticket, if I want to push for a fix.

Then I opened complain ticket AB3604, which was, again, rejected. They say it is working per design, and is not a defect, so complaint ticket is not the right process for it, I should open an RFE ticket.

As such, here I am, with an RFE ticket.