The VMAX (76 code) will not put idle data on higher tiers, even if there is plenty of available space on them.
We've recently installed a VMAX10k with three tiers (EFD, FC and SATA). FAST Policy is configured as 'free-for-all' with 100%/100%/100% for the three tiers, so the Symm can determine where to place the data.  After we started migrating data to the VMAX we could see the EFD tier fill up; I've adjusted the FASTVP Reserved Space to 2% so that tier is now 98% full. We could also see data come in on the FC tier and on the SATA tier.  Currently the FC tier is 35% full (total capacity 246TB) and the SATA tier is 18% full (total capacity 182TB). Hence, everything located on the SATA tier could easily fit in the FC tier...  I'm used to the VNX systems filling the higher tiers first. A VNX only pushes data to the slower tiers once the faster tiers are full. I would expect the VMAX to do the same, but is this true? Or did we misconfigure something?
Tier usage - SATA tier used when FC tier is not yet full