The allocation by policy feature allows new writes to come from any pool that is in the policy the device is associated with. If the policy only contains an EFD pool and a FC pool, new allocations will not come from the SATA pool in the array as that is not included in the policy. If both the EFD and FC pools are full, then a new write that causes a new allocation will fail. If you want writes for the device to potentially be allocated from SATA, you will either need to reassociate the SG the devices are in to a different policy that contains the SATA tier, or you will have to add a SATA tier into the policy.  Removing the devices from the policy will not work. If the device is not managed by FAST VP, new allocations can only be made in the pool the device is bound to. The allocation by policy feature only works for devices that are managed by FAST VP - the devices need to be associated with a policy.
I found this doc in powerlink that says the following:   Fill Thin Pool  FASTVP will attempt to allocate from most appropriate tier based on FAST VP performance metrics and policies & if the pool is full , alternate pool will be choosen for allocation. So till any other pool has space your safe. But still monitoring will be always needed if you over subscribe your pools.   FAST VP will not fill up a pool completely due to the PRC setting on each pool.  The PRC (pool reserved capacity) reserves a certain percentage of each pool that cannot be used for FAST VP movements.  By default, the PRC is set system-wide with a value of 10%.  What this means is that when a pool is 90% full, FAST VP will no longer move data into that pool. It can, however, continue to move data out of the pool.   Thesystem-wide PRC setting can also be overidden by setting a PRC on each individual pool.  The best practice recommendation is to set the PRC to 1% on pools that have no devices bound to them.  On the pools where devices are bound, the PRC should be set higher to reserve capacity for new allocations resulting from host writes.   VP allocation by FAST policy.  This allows new allocations from host writes to come from any pool in the policy the device is associated with.  So, even if the FC pool fills up, a new allocation could come from either EFD or SATA.  As long as the array is not oversubscribed (the bound pool can be) all new writes will be successful.   My real question: So, If I understand, if I have a SG with a policy for EFD and FC only, and both POOLs becomes FULL, it will not put the new writes to the SATA POOL because is not in the policy. Correct? I have to put the SG in another policy where POOL SATA is included, or removing the POLICY it could work?
What happens if a Thin Pool becomes FULL in VMAX FASTVP?